There has to be a grounding screw round here someplace... oh there's one

Little question.
Do these boxes come with the knock-outs already removed from them?.
Just wondering, because there are 3 on the side of that box and only 2 are being "used", why the extra hole?.
Has to be good for spreading smoke and heat.
People should be shot for doing this sort of thing.

Trumpy,
Wassa matter? They don't have "heat relief", aka Ventilation in New Zealand? Heck, no wonder you guys need so many firemen!!!!

Trumpy, it kind of depends on who was wrunning the punch press that day whether the hole is plugged or not, and how @#$%^& hard it is to get out the KO

How come they're called knockouts anyway?

All of them ever I've seen knock in.