Sorry for chiming in a bit late on this one, but from my own experience on climbing stairs kilted:
The wife and I went to "Dickens on the Strand" in Galveston last year. we had to ride the ferry to get to the island, and during the ride I need to visit the restroom, which is on the upper deck on the ferry. The only stairs are fore and aft and verry open on both sides, not to mention it's very gusty on the water. I walk up the stairs, and the gusts blow my UK up in front AND back! I needed both hands, one in front, one in back to keep the kilt down, to avoid giving the poor lady behind me a show, and I prayed that the boat didn't pitch while climbing the stairs without using the handrails. After using the facilities, I had to employ the same "one in front, one in back" hand coverage to descend, and I think next time, I'll bring an army surplus bedpan or wide-mouthed bottle!

Matt in Texas