1. No but looking at an allergen list is a super quick way of seeing if something isn't vegan without bothering anyone. And it shouldn't feel like an unreasonable request to the places serving food.
2. Because nothing says fun like wasting time trying to find out whether you can eat at a location or not. I thought this thread was about increasing revenue? Because food is a great way to do that. People with dietry requirements make up an increasing part of the population, and getting those people to spend money at the parks helps. So much of the snack foods around the park are advertised to children, and it is slightly jarring from the park experience when all your food is from outside the park. Kids are great money makers in that area. It is harder to leave the park when you have little ones and you don't have access to a car. There are options in the park, but I had to hunt for some of the more out of sight ones over several days.
3. Guest services don't have that information. When you ask the answer is "We aren't sure, just bring your own." I know because I did ask when a dairy intolerance was my main concern. And it wasn't something that was easy to access at Dirty Harry's either. I made sure to ask first thing in the morning when there was no lines but it still took a while to get that information.
And to everyone who has mentioned Rick's, the salad bar was one of the options I was talking about. They were a little hard to talk to when I asked whether things were dairy free. $29 for a subpar salad bar is a lot, but finding out if the pasta has eggs in it in it might make it worth it to have some filling options too.