is it safe to be behind a microwave while it's on? In our restaurant we have the microwaves in the open where you can be behind it while it's on. Usually in normal houses you don't see the back, only the front. Is it safe to be behind it while it's on? I know it sounds like a dumb question, but I heard someone say once that it wasn't safe, because of radiation or something. just wanna be safe.
A home grade (or dual use unit), unless defective beyond reason (eg if there is a hole in it or an interlock is broken) will be always safe from all directions, since any risk of harming persons or animals and/or creating radio interference (Microwave ovens share a frequency band with WiFI!) behind a wall or in the room below or above is unacceptable.

Same can be expected to apply to a commercial unit, unless it would be some very special device not intended to be used as a normal microwave oven (eg one meant to be operated on a conveyor), which can be expected to come with very clear warnings attached in that case.