Not all league players are inconsiderate of others, as you have proved here. But, far too many think that their league match is all that matters in the entire room.
Here's what happened to me a while back- I go in the room, see an open table at the end of the row. I ask the counter guy if I can rent that table, or if the leaguers have it. He says I can rent it. As soon as a friend and I get the balls on the table, the leaguers pull up some chairs right next to it!
I politely asked them to move the chairs and stand behind the counter where the observers are supposed to be. The two girls do that. Then, their captain tells two others girls to put the chairs back there! I again politely asked them to move. They both just gave me a smirk like "what are you going to do about it"? My friend was getting quite perturbed, so I told him to watch this. I purposely left the cueball up at that end of the table, then looked at the girl sitting there, asked her again to move, got another smirk, and then I just straddled her chair with her in it, bent over, and took my shot.
Right away her captain says he's going to kick my ass and wants to take me outside. So... I unscrewed, put my cue back in the case, put my jacket on. Then I walked right over to him, told him "come on outside, I'm ready. By the way, I fight better than I play pool." Poor guy almost wet his pants.
I then told the counter man what just happened, and he told me "no charge". He also told me that he was sick of the leagues there. They don't spend anything, won't ever pay for any table time, and drive everyone else off. He told me to come back in a week or two and I would see some changes in there. They took half the tables out of the room because of the leagues ruining the room.