Whiel I agree that calling for reports should be bannable, it is not OK for Riot NOT to let us know.
I am a long time player, I have been toxic many, many, many times. I have called for thousands of reports.
It is fine that calling for reports is bannable. After all, it is Riot's game and it creates a negative enviroment. However, despite playing the game for over 5 years, I only learned that reports are bannable recently. Maybe it was just me, but my friends (also long time players) didn't know about this either.
I learned this the hard way and it sucked, a friend got permabanned because he found out too late.
What I say we do, is put a red warning sign every time someone types "report" in chat that reads "You can be banned for calling for reports" or something along those lines. If someone is fine with that then let them go ahead, but my ignorance got me a 14 day ban, a 25 game chat restriction and other punishments in the past.
E.G. if @Riot Tantram responds to this, could you please PM me (or something like that) my full punishment history, going as back as my account's creation if possible? Thanks.