There have been a lot of cheaters recently in Codeforces. Currently, Codeforces just skips theirs solutions and does NOT reduce their ratings at all.

In Codechef, cheaters are punished by reducing their ratings drastically and sends them a email notice. If you get caught cheating repeatedly (2nd or 3rd time), your Codechef account gets banned permanently.

MikeMirzayanov It would be nice if Codeforces implemented the same punishment to cheaters.