The range I frequent is one where a woman rented a gun and committed suicide. Maybe I'm just a little paranoid, but when I go to the range, I don't trust anyone as anyone could be the next nut job to commit suicide, but may want to take a few others with them. I watch/observe everyone that's there. If I get a bad vibe, I'm outta there.
I don't feel safe around people with bad safety/firearm handling practices either. This range has thick, bullet proof glass separating the lanes. During a session a while back, a guy had a problem with his Glock and it didn't fire for some reason. He leans it over, pulls the trigger and BAM, right into the glass. I packed up and left.