We had that at a hall here in the mid 90s when pool was getting huge. 26 tables, and there was a waiting list every Thurs-Sat night. 2 hour limit.
But the way the bartenders were told to manage it, was to tell everyone about the 2 hour limit, and if it was a single person or couple only playing pool and not drinking or spending anything, then enforce the policy. There was never usually much of an issue as they were told before they started. And when it was a group of people spending a small country's GDP on food and drink, well you just let them stay on for whatever how long they wanted to.
It's actually not a bad idea - you're not going to keep the lights on with just the table time. If you have a group of drinkers waiting to get on a table with a single guy practicing and drinking tap water, from a business standpoint, the choice is not hard.
And as a player, I understand it. Our local hall here gives us a $5 all you can play deal for all league players, but if the place gets full and another customer comes in looking for a table, we either switch to full hourly rate or give up the table. Good business I think.