I have a tablecloth I put on the playtable during crafts - no cloth no craft. That way table stays clean for meals. So they identify with the cloth. As soon as that goes on the table the older ones will come asking wha we are going to make. It is just a cheap thing from the dollar store meant to be used once for a party so nothing fancy and I just replace every few months if necessary. Easy to just pull up and stuff on the shelf with the crayons.

My thing about the food is confusion. I am trying to teach the kids not to put stuff in their mouth but then put them in their high chair and give them an orange carrot and expect them to eat it then give them an orange crayon and get upset with them if they eat it - confusing for the child. So until they are old enough to make the distinction themselves I don't let them have craft supplies in their chair and they don't do the craft if they are unable to sit on a regular child size chair at the table.

One of the reasons they get books in their chairs is that books don't ever go in your mouth even the plastic ones at my house when you are playing. Books are special and we treat them with respect. Therefore there is no confusion with books in the highchair because they already know what they are for.