My respone is to the OP. It was a "fixed" microwave and the recept was passed through the bottom of the cabinet above. Therefore the microwave is not blocking the cord thus anything could in theory can be placed in the the cabinet. Since the cord is unprotected, it is exposed to potential damage. It is not a matter if anyone seen or heard problem. An unprotected cord put in a place in an area of potential damage is not exceptable (NEC 400.8(7)). If the recept is behind a fixed microwave, someone has to go out of their way to damage the cord.
As for your refigerator comment, if both receptacle and refrigerator are properly installed there will be no damage to the cord.
Wait, since when is a cord and plug to an outlet considered "unprotected"? Last I checked, your argument applies to every receptacle in a house- you're not putting covers and conduit over the others, why worry specifically about this one?
The microwaves are UL listed, the cord exits the top, and the instructions specifically say to drill a hole through the cabinet. This is cut and dry, it's acceptable. To do it any other way would be illegal.
