I never have, but I never would, either! I canNOT imagine leaving the trigger uncovered. But, then again, both of my carry guns are not protected by an external safety (Glock and Kahr).
There was a local story recently of a man--stoopid man, but a male species nonetheless--who was mexican carrying with sweat pants. It started to slip, he reached down to grab it, it fired, and he yelled, "I just shot my groin!" in the Lowe's he was shopping at.
Steel clip is just one step better than mexican carry, IMHO.
.45acp, .40 S&W, 9mm, .38 Spl, .380 acp, 22lr
12 gauge, .223/5.56x45mm, 30-30 Winchester
2 Chron. 7:14 Christians must seek His face