Because they reserve the room for your party only they require a minimum payment of 4 people regardless. I had a party of 3 but still had to pay for 4(one didn't show up) to book it. It's a real fun experience!
Yes, jakaylalb1 is right. The minimum purchase is 4 people at about $100. You can still go with less people, but you have to pay for 4.
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