I have to respectfully disagree. I used spirit vision with the door open in the ship captain's room (Driftwood Tavern) and the magisters arrived saying something like, "did you just use source?" and they were not amused.
Oh, yeah, I also got into trouble for the same thing. Magisters seemed to be a bit twitchy with overt magic usage and I learnt not to engage in that particular pastime in their vicinity. Not unless I wanted to fight about it.
