Yes, they do. You can do advance research but things change very quickly, and important things, leading to frustration both for guests and cast members.
Even if you do research beforehand, you're still going to ask for the ingredient book at Casey's, because in the meantime they could have changed suppliers. That's just how it is. So I ask you, do you want to be in line behind me as I take the few extra minutes to read the ingredients and figure out what I can/can't eat? or would you rather rush by me waiting in line at the special diets kiosk, mock my gimpy intestines, and get your hot dog a little faster?
This option pleases us both. The kiosk would have the most up to date information - computerized, hopefully, based on what chefs have ordered that week.
Eager to see how this works.