The idea that any mundane authority has or even could have the right to investigate magi of the Order of Hermes is exceptionally dangerous to the Order's independence. So much so, in fact, that I would expect any magus recognizing and cooperating with such authority to be promptly charged with Endangering the Order.
This is much more likely. I have pondered the idea of a Savantism+Puissant/Affinity/Cautious With* grog on occasion for exactly this purpose, though I probably wouldn't minmax quite that hard for a character I actually intended to play.
* Options include Folk Ken(magi), Perception(clues), Hunt(tracking), Intrigue(plotting)