When you rage quit in league
http://imgur.com/8HuPaCt
Then calm down 10 seconds later and try to get back into your match
Then calm down 10 seconds later and try to get back into your match
When you have an issue with the firewall when you attempt the enter the loading screen and have to restart the client to enter the game, then can't log-in until about 15 minutes have passed.
I see what you mean, there have been plenty of times where I just quit a game I'm in, with full intentions of joining back. Just to have the servers tell you to fuck off. xD I stopped because I got too paranoid of this exact scenario. RIP