Do you still have to pay if you're not playing?

I would have to assume that would be a definite yes since there is no way to police once your'e inside. Although its a really cool spot and its only around 8-10$ Just drop the mula and have some fun ;)

Yes, unfortunately you do. Maybe once you are inside you might get tempted to play. so it won't be a total loss of your money.

Yes. They charge a flat admission fee. Once you're in, you can play as many or as few games as you want.