$1 hold on debit card from a bar for playing pool?!

Some friends and I went to a couple bars last night, and the 2nd bar we went to had some pool tables, so we played a couple games. In order for us to play pool, though, the cashier had to have someone's debit/credit card in order to swipe it on their computer before we got the pool balls, as collateral or something, to prevent theft from people walking out the door with the pool balls. We paid at the end of our game, but they needed someone's debit/credit at the begining. They swiped my card, and I asked them if there will be a charge for swiping, and the cashier said no; however, I check my bank account just now, today, and there is a $1.00 pending item in the debit column of my online bank account from that bar. I called the place up today, and the manager said it would go away, but how long will it stay under as pending in my account for? Shouldn't the $1 pending come off right when we took the pool balls back to the cashier after our games? I'm not worried about it, just don't know if they will add gratuity after they take the $1 away just for pool because that was a separate tab from the drinks, and sometimes bars will add a gratuity charge, but don't know if they do that for games of pool at some places?

*2nd question, if you have time. Also, at the 1st bar we went to earlier last night, they don't even ask for your card for collateral before pool, and the one that doesn't need a card is a private membership billiards bar for $3 a year. So, why do some pool places ask for collateral and some don't? Just another question I was curious about. There's some pool halls in our area where we live that don't ask for collateral. Does it have to do with how big and nice the bar is?