It was "Scotty" Thompson in his book that called a too long kilt "trollopy"

My waist is still, after many decades still smaller than my hips, so that is not a problem if the kilt is of the proper fit to start with.

For those with slippage problems, I strongly recommend braces (suspenders to the Yanks) as a valid means of keeping the kilt at the proper length. I strongly recommend sewing on buttons for attachment, as clips can damage the fabric, over time.