You see, I disagree with a mundane seeing anything in relation to a spell being cast until the actual effects are seen/felt (generally it's mainly Indirects that have visible effects), so that is one thing that I do house rule to change. I alter the test to notice spell casting to be Assensing rather than Perception, but I think that Magic should be the Great Unknown to a mundane, and it also gives more of a reason to have a team-mage.