no.. i just randomly joined a hacked lobby GW that became FFA HC hardhat jump hack.. and since then i cant see the uav
Try deleting you patch_mp file. Loacated: C:\Program Files (x86)\Steam\SteamApps\common\call of duty modern warfare 2\zone\english
And then verify your game chace. Right click MW3 in Steam Library - Properties - Local Files tab - Verify integrity of game cache.
I don't think this will work, but that file sometimes gets changed when you join a modded lobby.