Using belt loops can be a bad thing. A couple of days ago, my wife told me that I had a lump or something in the fabric, near the top of the kilt (below the belt); it turned out that the belt was pushing up at the top of the loop, thereby pulling up the bottom of the loop, and deforming how the fabric hung. It wasn't evident at first, because my sporran strap was outside of the loops and covered where the loop was pulling the fabric up.

I'll just not use the loops anymore; I hadn't at first anyway, but was trying it with the loops to see if there was any difference. I guess there was!