You know… I'm not actually convinced that the Templars would always notice if you got possessed during your Harrowing?
Like they don't have the best track record for noticing that people are possessed? Sure if you're glowing, speaking in double voice or visibly mutated they notice. But if you look normal and act normal, they don't.
To all appearances Templars don't have have any special ability to detect possession. Special ability to provoke spirit/demon flare up possibly yes, but that is by being a traumatizing, violent, threatening, abusive and all round a terrible person that their victim knows can and will murder them.
'Abominations' (for lack of a better word) seem to have some degree of adjustment period, but it isn't always extreme and seems to act up mostly in response to strong negative surprises.
A patient, calm level headed spirit/mage pair who entered into the possession willing and in full anticipation of how they would need to Not React to the Templars. Or a very skillful demon who managed to take possession of a mage very smoothly in full knowledge of the situation they would be getting into. These seem like instances were a Mage could walk away from their Harrowing possessed without the Templars having a clue.












