Is this a form of soft trolling?
I've seen some junglers just jungling all day, then soloing the other team 1v4/1v5, and goes back to jungling without ever a) helping in team fights or b) taking any objectives. They actually RAN BACK TO JUNGLE when all the enemies were dead and they were right under an enemy's inhibitor turret with a minion wave, without the slightest intention to attack the turret. And since they got all the kills and all the rest of us were underfarmed by a lot, we would die 4v5 constantly with the only fed person on the team on the opposite side of the map farming double golems. Oh and yeah they have teleport too...
Provided I mostly play bot games and before you say bot games don't matter, that's where most beginners and new gamers (myself included) start and learn about the game. It's very unwelcoming for new players to be teaming with people who are obviously not team players at all, especially since league is designed to be a team game as far as I know. Is there a way to discourage such behaviour?