So, apparently

The new system + the "riot tribunal warriors"

Will in fact permanently ban you over one to two bad k.d games.

http://boards.na.leagueoflegends.com/en/c/GD/376Zba2l-lol-what?show=flat&page=3

I can already tell you high mmr population is going to be plummeting this season lol.

Almost every single game in plat -Challenger is a one sided stomp. So, if you're on the unlucky end and end up on really bad teams three to five games in a row, enjoy your perma ban.

i'm glad I decided this was my last season of playing anyways. Make sure to read the very last post on that forum so you can get a real good glimpse of Riot quality.