Don't work, at least for me and everybody else I know.
For me personally, they've only made me more toxic than I normally am, because I'm being restricted from venting out my toxicity to it's fullest extent, so then I end up saving my available messages, and let out 200% flame the moment I can, which is different from my normal 55% flame per message. Not to mention, even in the games where I'm not trying to make the person that irritates me most cry or AFK, starting with 3 messages and getting one new message every 5 minutes or so is not enough to properly communicate with your team.
Honestly, half the time I'm chat restricted, people either assume I'm just rude because since I'm not communicating, or simply try to report me for "griefing" because, in their logic apparently, not talking is the equivalent of not trying/giving up.
I've said this many, many times, but a better alternative to Chat Restrictions is simply giving the players the option to mute themselves. There's a difference between having restrictions placed upon you, and accepting them willingly. Not to mention, by choosing to mute themselves, the player is obviously showing that they have enough self control and self awareness.
And yes, I meant to put "10+ Accounts" in the title because I've had so many account permabanned that I genuinely don't know how many I've made, anymore.