The Bjornaer sense magic mystery plus the Trust Me effect would seem to be a powerful combination - especially if the capacity to pick up bad vibes from the Gift is a targetable sense.
edit: I'm now picturing a wild faction Bjornaer specialising in ReMe and attacking civilization from within. A war here, an economic collapse there, a peasant's revolt somewhere else and population pressure on the wild is relieved without ever getting ones own claws bloody.
You mean aura of ennobled presence 
All of the above goals of mundane chicanery are possible without needing to hide your Gift effect. Where it breaks from the regular Wilderist stereotype is the magus is using the tools of society against itself (gaming the system) rather than the more usual 'rrraarrr, scary wild man in woods!' model. Any wilderist with sufficient intrigue and some clever selective applications of ReMe can be as politically dangerous as a Tytalus magus doing the same. Possibly more dangerous, simply because no-one expects the Bjornaer Inquisition! (cue appropriate 'whoosh' noise, etc).
I also say that the Gift penalty doesn't represent a targetable sense. YSMV, of course.
Granted you don't have to hide your gift but it helps and it makes it harder for anyone to spot the hermetic crime. Targeting sight + sound + smell will do the job if giftsense is not an option.
Such a Bjornaer would make a great antagonist in a saga with a lot of mundane interaction.