Funny thing... As 'unsafe' as that is, my idiot catz figured it out the very first day. Avoid box fans without safety shrouds.
/johnny
An awful lot of people had home made fans when I was a kid. They would use an extra electric motor placed on a pipe stand welded to an empty car wheel. The fan itself was a blade from a car radiator fan.
I never heard of anyone ever getting hurt with one of those. Stupid people did not survive long in those days.
Never heard of anyone accidentally getting shot with an unloaded gun either, always was on purpose with loaded gun.