It was pretty inconsiderate of the guy to do that with someone else's gun.

Years ago there was an excellent gunsmithing firm specializing in the Colt 380s. Their website was Colt380.com. One of the principals retired and the other died and that was that. I have several of the Colts they worked on and all are excellent. The point of this reply was that with every pistol they semi-customized, which included a trigger job, they warned not to ever let the slide slam forward on any such guns. I don't remember the specifics but the warning was emphatic. The Mustangs were SAO and the Ponies DAO but the warning was the same for both. I mention this as those guys knew what they were talking about.