Training scars of various forms are probably where there is the most validity to the shooting sports will get you killed on the street. One of those is holstering or scanning with an empty gun, which is why I brought it up here and included a possible solution as well.
I am guilty of this in the carry matches. As long as there are at least 7 rds in the gun (reload after 6 without going to slide lock), I often don’t change mags after a stage. I need to change that practice.