Being good!

We were invited to come along with our friends' to Chuck E. Cheese for a play date because Jacob had gotten a good report from school. Of course the kids' always love to go here and have fun and this day was no exception. The pizza is very tasty there and papa kept them pumped with tokens. Now with that comes the situation that I'm personally struggling with; That by being good they are going to be rewarded in some huge way for doing something that they should already do just because it is the right thing to do. G. Came home with this report and ask, 'What are we going to do?" because her report was outstanding. I said that I wasn't sure because I'm not. I've always given to my kids' for being good, but when do ya stop, when does it get too out of hand? Not saying that going to Chuck's is over the top. It certainly isn't, but our kids' are still little and pretty inexpensive. When they get older is what I'm worried about. Am I over reacting? Should I just say a job well done or do I get all dramatic about good grades? I'm merely asking as a parent because I really don't know, this is not meant to be offensive in any way, So please comment your thoughts.