So... stating the rules is met with a permanent ban now.
Apparently someone was hit with a permanent ban after informing another player that the 6-letter F word is against the rules, in response to their use of it.
That is the most blatant ignorance of context we've gotten. If Riot can't afford a Support team that actually looks at these cases, then they shouldn't be banning people arbitrarily.
It doesn't matter if the agreement says that they don't need a reason to ban you. That doesn't make it okay, and certainly shouldn't be tolerated by the players.