First of all, nobody is under control, i know that Riot forgives too much, So they know that nobody is perfect and everyone make mistakes.
Not exactly everyone, maybe like 5~10% of people never flamed, and those are really unique and special and they have risen and created just like that.
Edit: And by *maybe* i meant to say its not a clear % first,
second, i said ( Never ) Never flamed, Look at you, did you never flame? Never? if you did once out of 10,000
then take yourself out from the 10% of people that never flamed.
-if someone muted himself, will not be able to chat during the game, and cannot unmute himself back.
-he will be able to use Pings as well.
Note: its not easy to bend the 'Enter' key for most of the community they dont know that.
A simple mute self key would be easier.
Note: if someone have the idea that mute self key will lead to more trolling, Nah its actually the same nothing changed, if someone want to troll a game Logically he will troll it without being toxic in chat.
Also its not harmful, if someone muted himself, Logically means he won't communicate with team, doesn't mean he won't play during the game.
Everything will be the same, but Less toxicity, if you feel harassed from toxic players upvote this,
So they will never harass you anymore!.
Edit: you can mute yourself every 4 games once, every 5 games once, or you get Extra number of mute self key if you didn't use it.
Otherwise it will be very clear that if someone used it to just troll.
its easy to dedicate trolling but not to stop toxic.
Best Of luck