Cloak/Spell of Non-Detection will help your Thief against the True Sight.
Somebody's entering the room! *casts True Sight*
Ah yer being paranoid again. It was most probably just the wind.
No! I swear I heard footsteps!
Rightttt, and where is this bogeyman of yours then?
*whisper* Just behind you sticking a knife through your neck.
ARRGGGHHHH!!!!
AHHHH!!!!
