I agree with this in part, but even if they can't do the literal work listed in the actual ad itself, then that just makes it dangerous. They're going to be around hot surfaces and boiling oil and sharp kitchen implements I presume they will be kept away from hot surfaces, boiling oil, and sharp kitchen implements while the real employees do all that stuff, and that there won't be customers in the restaurant at the time. But I'll lay money a kid is gonna get hurt by those things anyway, because they're as young as five and... well, anyone who's dealt with children knows they get into everything. You're bang-on right that there is no way in fuck this is a good idea.
Edit: I also want to clarify, I'm not aiming any hostility at you. I'm just really upset about adding yet another bead to the child labour bracelet America's making itself.