Ever see someone walking around the sporting clay range wearing flat soled shoes right after its rained? I certainly don’t want to be near them when they are shooting. And this is way worse. You see him take that little step back? He could have tripped and he still had his hand near the trigger at that point. He could have shot someone by accident.
If you are going to shoot wear the right equipment, and make sure it fits and is in good working order.