I see that kinda of stuff all the time, and worse. There was the time a guy walked into the range carrying his pistol in his hand, not cased or holstered. Yeah, it was loaded. And then there was the guy who loaded his pistol on the target bench and turned 180 degrees sweeping the whole line getting ready to shoot.
Ever notice all the bullet holes around? Ceiling, walls, floor, etc.
When I see more than a few folks at the range, I'll either leave, or wait till they are done. Its tough to practice and keep track of more than 1 or 2 other folks.