While I was going to dealers school, I worked as a change boy (back in the day when we carried over 50 pounds of coin on us -no carts- and no matter where you walked in the casino it was uphill!) and I was told when I got hired that if someone under 21 asked for change for a dollar so they could make a phone call I was not allowed to give them change.

I've seen cage cashiers tell kids to walk away from the cage before they would cash in their parents chips.