How 'strict' is Riot's stance on Negative Behaviour?

I've seen a hugely increasing amount of negative people, those who are giving up, wanting to surrender and not to win. It seems that _every_ game where my team falls behind, there's at least 1 person saying something of the following 'gg open' 'idk about this game any more' 'go ff' 'go end' 'report this jungler and end' Although people are normally 'joking' when they say these things, it still creates a horrible atmosphere, and IMO should really be something that gets punished, as to me this behaviour is not OK. I always report people who say these sorts of things, but I can't remember the last time I got a message up saying that a player's been punished. I was wondering Riot's actual stance on this, and how strict the punishments are for people who type these things?
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