Its find to have a nice subtle plaque somewhere somewhat out of the way.

A big ole Garden with a sign saying DEATH HAPPENED HERE - SOZ BUT HONESTLY IT WAS OTHER PEOPLE'S FAULT would definitely be a bit weird.

A few (I think three) drag racers have been killed at Willowbank Raceway (drag strip) in 35 years, one at the very first meeting.

Only one has a plaque, it's a bit bigger than an A4 page. It is in a garden, beside a main walkway but not right on the path and is done in a subtle way, it is not in your face.

A second racer who passed in his sleep has a plaque at the facility too, done in a similar manner.
One of the founders has the actual track named after him as well, with a lit street sign pointing down the track behind the startline.

Those examples show it can be done tastefully. It will be harder to do it tastefully at Dreamworld due to all the attention and the fact that those four people thought they were safe. The drag racers all knew that there where risks even with safety equipment.

Okay so I'll elaborate since I've had more time to think on it.

A simple plaque on a wall I think is fine for a theme park.

A designated area/garden would be weird but for different reasons:
1. If it's a garden that's named and/or put on the park map as an 'attraction' even if it's not meant as the typical definition of an 'attraction' (and let's face it, Dreamworld seems to think even a bunch of ~nice seats~ qualifies as an attraction these days so it's possible) then that I think is weird. Again not saying disrespectful or tasteless that's a matter of personal opinion but definitely weird.
2. If it's a garden that's NOT on the map or 'officially' named that's almost as weird, just in a different way. For example imagine the parent of a young child potentially unaware of the TRRR incident (possible, especially for future or foreign visitors) and then entering the garden and having to explain what the plaque says. Kinda brings the mood down for a family theme park and at worst might even deter people from visiting again.

Granted this is all just my opinion, maybe people in the general public won't care at all either way nevertheless its been on my mind.

You've gotta find a fine line of accepting that your park killed people while also not shoving it in the face of everyone that your park killed people. 

Luna Park Sydney does indeed have a plaque for the Ghost train tragedy. It is in a part of the park not many people go to but many can easily walk past. The plaque is tasteful while being heartwarming but also confronting to some.

I believe this would be the best way to go. Does not need to be something bigger than an A4 piece of paper. That being said consent from all families would definitely be required.

A garden idea while being nice could be somewhat complicated.

I think a garden bed, no bigger than 3mx3m in a corner of the old goldrush area, not able to be walked through, with a small stone, and a plaque (again around A4 size) recording the normal memorial details (similar to the luna park ghost train plaque), with some nice native trees or shrubs, kept neat and tidy would be fine.

It shouldn't be any sort of 'walk-through' attraction, and it shouldn't be marked on the map in any way.

Something like this

I'm confused why this is being discussed in such detail? Memorials aren't new and don't need to be innovative. As @AlexB has above, just do the normal. Small garden bed or Tree with a bench, specific plants/flowers chosen by the supporting families.

While a garden bed does have that personal touch I worry about the upkeep of the garden bed and the damage that could occur. Unlike garden beds in cemeteries, those don't get visited as often as say one in a theme park.

It is indeed a great idea for the garden bed. I just don't feel its the right fit as pointed out above.

2 hours ago, StingRay said:

I worry about the upkeep of the garden bed

If they can’t keep a garden bed in a presentable condition I have serious worries about their ability to keep rides operating.

3 hours ago, StingRay said:

While a garden bed does have that personal touch I worry about the upkeep of the garden bed and the damage that could occur. Unlike garden beds in cemeteries, those don't get visited as often as say one in a theme park.

That's an advantage though. Memorials in cemeteries do get vandalised from time to time, but that's because they aren't frequently visited.

The spot i'm thinking of (where the old stagecoach once stood - near the Eureka entrance) isn't in direct traffic line, but its clearly visible. A small decorative chain or railing around it is theme-park code for 'no entry', and with the new coaster, the area would have enough common foot-traffic that anyone jumping the chain is going to be spotted pretty quickly.

Could this be the area for the memorial garden? Hence the clean up there.

42 minutes ago, Greg said:

Could this be the area for the memorial garden? Hence the clean up there.

Or maybe they're just trying to make it look presentable.

That is a completely unnecessary spot to put any sort of memorial. Wherever they put it - it should not be in front of an Ice-Cream parlour on the busiest street in the park.

3 hours ago, AlexB said:

That's an advantage though. Memorials in cemeteries do get vandalised from time to time, but that's because they aren't frequently visited.

The spot i'm thinking of (where the old stagecoach once stood - near the Eureka entrance) isn't in direct traffic line, but its clearly visible. A small decorative chain or railing around it is theme-park code for 'no entry', and with the new coaster, the area would have enough common foot-traffic that anyone jumping the chain is going to be spotted pretty quickly.

That spot would be a very nice location. You are right. If it would be done that way then not many issues should exist. I just worry mainly about the upkeep that's all. Its something that needs weekly attention. Yes, a plaque needs attention also. A garden would be better as I am sure several times a memorial garden was mentioned.

4 hours ago, Brad2912 said:

If they can’t keep a garden bed in a presentable condition I have serious worries about their ability to keep rides operating.

It's not that I worry the park cannot maintain it as such. It is the assholes who pluck flowers or branches off etc.

I know this is completely unrelated, but can someone tell me which year exactly did the Dreamworld logo change from the old logo to the logo we have now. I know it was sometime in the early 2000s but don't know exactly when

14 hours ago, Flynn_Smith said:

That is a completely unnecessary spot to put any sort of memorial. Wherever they put it - it should not be in front of an Ice-Cream parlour on the busiest street in the park.

I agree with everything you said here except that that area is on the busiest street in the park.

14 hours ago, StingRay said:

It's not that I worry the park cannot maintain it as such. It is the assholes who pluck flowers or branches off etc.

I'm sure the chain can be spaced suitably back from the more delicate elements of the garden. I can assure you if I saw anyone defacing or otherwise damaging the garden, they'd find themselves headfirst into the nearest garbage bin.

I would be planting 3 lovely big trees (one family member’s family reportedly don’t want a memorial) down the back in Corroboree and having a plaque saying “these trees dedicated to xyz). That’s literally it. 
I would not mention the accident or the deaths of why. 
That way there is something for the families to visit if they so desire. I’d keep it as far away from the accident site as possible. Firstly for the same reason, the family probably do not want to go back to that spot. Secondly you don’t want a big “death happened here” reminded, regardless of if it’s a big or small plaque, etc. 

 

I think the memorial should be as subtle and discreet as possible. It’s about about acknowledging the people for the family of the family so wants so.

Anything more prominent or public starts to enter the world of being for the park, and almost using the deaths as goodwill by implying “look how great we are, we care, here’s a plaque.”

 

I think subtlety is key. 
I’d also say don’t put it in a prominent area that is likely to see development because if you have to move it, that will just cause more outrage.