Yes, last Monday. MW2.
Went into a ground war game, was fine. Another game on ground war was domination, was swapped to Rust map instead of the servers choice, mod added fast running and high jumps. I exited.
Went to another ground war match, arrived with the game just starting and everyone running on the spot (I wasn't), I moved a bit then everyone died once. Knew it was hacked so left and entered another match, this time normal team deathmatch. Noticed I no longer had a silencer.
Exited that game to read my Clan tag as C*** and all of my legitimate prestige kills and barracks scores gone. Am now at level 1 in 3rd prestige (I think).
Luckily I was not 'hit' as bad as some people (see Chevinator123 above) who were literally reset back to nothing.
I haven't played it since.