It's known to get booted from their servers for no reason, and when you re-enter, it says you have been 'Kicked' in which no one ever kicked you in the first place. Hopefully Rockstar servers for GTA V are way more stable.
Well, there is two ways to 'kicked' from an online mode.
Either you were actually kicked from users, or the server became unstable and booted you for no reason resulting in a 'kick'.
If I'm being kicked because of the server becoming unstable then that would mean that it becomes unstable A LOT rofl. or its from other players. whatever the cause is I tend to just look passed it and move on.
And you just answered your own question.
This will be the reason why I stopped playing online.
Especially when I had my close friends playing then bang I would get kicked so would everyone else.
Now all I do is hunt flying rats.