Yes, but all usually dip out by around 2pm, and I did say 'in earnest'
I've seen load held up because someone was trying to shove the worlds biggest backpack in front of their feet. We know they have new trains, there may not be the space for baggage that there used to be.
As long as the grouper has people lined up at the gates when they open, I think this will actually improve load times. Unload will similarly improve if the loose item boxes are behind a gate - unload can dispatch the cleared train while people are getting their stuff, instead of waiting for the guy with the big backpack to extricate himself from the far seat.