T.F.
I would tip 20% or accordingly.
My daughter's boyfriend is a party host at Chuck E Cheese and they bust their butts making sure everything goes smoothly for the party then some people shaft them on the check.... pretty cheap and rude.
I am amazed at some of the stories he shares with us, good and bad. Some people truly show appreciation and some people just don't care.
Many of these kids bend over backwards to appease the picky moms and entertain the children. Most of them are working these jobs to help them get through school and save for college.
At least tip something, they are trying to help the little ones have a good time, no clean up for mom/dad, location is great because it is not in your house.