Does riot even punish people trolling?

Just lost my promos because of a ap jhin mid because someone accidentally banned his yasuo. I see people trolling cause they didn't get their role or for others reasons and it happens way too often to think riot even does their job to punish players like this. I'm assuming the "punishment" is very minor because people do it without hesitation when something doesn't go their way, I much rather have someone be insanely toxic to me than having someone go troll and throw the entire game.