well... If your mate's neck is on the line and the meeting is about her getting un-wronged; and it's the wrongers you're meeting with. I'd wear smart (but casual - in view of the weather) trouseriness and not let MY appearance distract. I think if you put a Kilt on it will become the centre of attention and perhaps reduce your chances of a successful outcome in the face of their prejudice. If they are wronging this lady without a care they'll certainly hold some contempt about a man in a "skirt" (as they would no doubt interpret it). Tread careful AK, for your friend's sake.