I'll admit to "fatality dropping" in ranked, though I usually only do it when I lose to the same guy twice or more times in a row (yes, I'm a sore loser).
I don't bother with doing my own fatalities either, as way too many people drop, and it really doesn't bother me. If I want to always score the fatality, I'll play Player Matches. Yes, this is bad for players who want the fatality achievements, but I guess this is just something those players will have to live with.