If a player requests a chat restriction he should be able to get one

First, a joke:

I'll magically pretend to grant your request.

Poof You're now at a 25 game chat restriction. Unfortunately your next punishment will continue to the next punishment tier, which is a 14 day ban. This did not help at all.

Now, for the real response.

If a person is unable to control themselves in needing to inform people of how poorly they're doing or needing to insult people back, then if you mute them, they're unable to express themselves. Because the mute did not change who they were, they still need to express their discontent. Now, because they're muted, the only way to do that is through trolling. Perm mutes turn ragers into trolls, which is not the goal.

The goal is to reform people or get them to leave the game.

Riot isn't your babysitter. People who need chat restrictions need self control.

Bottom line: get some self control and that'll help you avoid a ban more than a chat restriction would.

Don't you get a limited number of lines to use when you're chat restricted? Which means you can still technically type toxic things in chat.

So, is this an effective way to save oneself from another punishment? No, not really, imo.

Instead, I would like to share what I do to stay within the boundary of Riots law.

I don't type anything in game. At all. I don't react to anything anyone says with words. If someone wastes their useless words on me, aka "0/3 botlane gg feeders" or something to that extent. Muted.

Instead, and here is the important part. I ping proactively. Enemy wards I've spotted with the new ward ping, objectives when they're close to being up so we can maintain vision dominance in the AO. Make sure you also ping enemy jungler movement for your laners that may be actively trading or CSing (aka not looking at their minimap). Another helpful thing to do is to ping enemies directly, preferably ones to collapse on with a flanking pick. Ping your important cooldowns, like exhaust, your ult, item actives (locket, redemption, empty sightstone)

Ahem, I apologize for that, I started to run off on a tangent there, the point is this: don't waste time on pointless idle chatter consisting of past events and useless whining about teammate performance. Don't retaliate to flamers and trolls in chat, mute them and focus on the game.

One one hand, I feel your plight, but on the other hand I don't think Riot's gonna do anything about it. Probably your best bet here is to unbind your chat key and get approximately the same effect. Or just /muteall as soon as you get into game. If you do that, it might be wise to give the rest of your team a bit of a heads up that you're not gonna be able to hear them in chat.

You might be able to rebind the enter key so you can't open the chat, but then you'd need to manually mute everyone on your team individually (vs /muteall), you can already turn off all chat in the settings. That'd have basically the same effect, in the end.

My approach has been to mute anyone who starts to complain about a teammate immediately. I also disabled all chat a while ago. If a person starts to spam pings, I mute their pings. I don't respond, I don't tell them what I'm doing, I just mute them and respond to everyone else as normal.

I, personally, do not think that, but I do just mute people because I have no interest in listening to their toxic crap, if that was directed at me.