Also speaking only for myself: I see a very real possibility of posters using this as an excuse not to mend their ways in a timely fashion, i.e. “I see that Poster A has 5 warnings, so I really have nothing to worry about for another 4 warnings. I’m going to get a couple more shots in!”
We have enough complaints about partisanship as it is-such a change would increase it dramatically, imho.