Hey, my names Chewy, I'm a member of the Angry Scotsmen RC. I've been told I might be of some help here.

All you need is 2 safety pins and a good magnet (mine is a 16lbs from ACE). Sit on the bike with the back of the kilt under you. Place one leg on peg. Rap kilt around leg tight and pin together. Put leg on ground making sure kilt doesn't rip and repeat with other leg. The magnet is placed on the front of the kilt securing it to the gas tank. Nut huggers can be worn too(bugs suck). Not sure if this works with crotch rockets, don't think so though.
If safety i sure number one concern, it should be noted that this is no more dangerous than shorts (which are dangerous), and that steel toed boots have been know to rap themselves around toes to the point where the toes have to be removed. This, of course, is only in the event of a crash and other instances where road-rash can occur.

P.S. they're called SAFETY pins for a reason.