I've encountered this issue in a couple games now. In a tie, the victory can be attributed to the "defender," that is, the person who maintains the status quo. In the context, however, of someone disguising themselves or hiding, is the status quo "This person does not know I am worth investigating," or "My identity is clear?"
In-game, of course, we went with the GM's decision that the /intent/ of the player in hiding was the aggressive action, and so the tie went to the person being duped - the observer. However, I feel like the context of skills in which one hides indicates that the status quo is "not arousing suspicion;" avoiding the attention of an aggressive observer.
Where should the tie fall? Who is the aggressor?
Apologies if this has been discussed, didn't see it on a search.