Back in the 80's when I'd go down to Frankfurt, GR to gamble at the Billiards Cafe, playing 8 ball last pocket with a player called the Professor for a $1,000 Marks a game, ($500usd) the room owner would shut down the other 2 tables near the one we were playing on because there was standing room only because everyone wanted to watch. The owner of the room would go around to everyone watching and either collect a bet, or tell them to leave because he didn't allow watching for free. After he collected and covered the next round of bets, he'd signal us that we could go ahead and play the next game. This would go one for hours and hours, always having to wait after every game for the room owner to collect and cover new bets, and kick out anyone just standing and watching. I don't know how much the owner made on some of those nights, but one night after I had won over $10,000usd, he gave me a tip that amounted to another $10,000usd!!!
How many times have you seen people just standing around watching 2 top players going at it, being entertained, for free!!
If I were to open another room on the basis of $20 an hour for table time, my policy would be to all the watchers, keep something to eat or drink in front of you at all times, give your receipts to the players your watching to cover their table time and keep watching, or leave because customers pay, watchers leave! Not making any money off of you anyway, so I've lost nothing when you leave either!!!