I always face this issue! As in,
I am one of those players who join a game, then immediately quit, sometimes multiple times in a row for the same game.
I join a table, and if it was 3+ players I watch the seats getting filled, then suddenly "I" quit (the game quits by itself as if I left the table). I see my seat empty, and the chat log says that I left the table. If I was quick, and lucky, enough to grab my seat back it might quit again, and again, until it goes through and the game starts, or someone else would grab that seat before me.
I always assumed it was a feature to give preference to premium members, and I looked at the forum but only found this thread
https://boardgamearena.com/forum/viewtopic.php?t=34559 where they assume that people are quitting willingly. It is really annoying, but I cannot complain since I'm using this site for free.
I would be interested to know if someone else is facing the same issue, or if there is a reasonable explanation.
PS: I mostly play TTR but I've faced this problem in other games as well.