Contractor wants to remove the cord and hard wire a refrigerator in a commercial kitchen. Reason: It keeps tripping. I told him if he removes the cord and hard wires the refrigerator, he is altering a UL listed (hopefully) piece of equipment. Not only that he is dealing with the fact that they're probably dealing with a piece of equipment that need repair. Someone could get hurt.

I agree. A fridge or A/C that is tripping the GFCI usually has in internal short in the compressor. I have proved this several times using a current probe on a scope and an old style 3 prong adapter with the pigtail. (actually an accessory for my Ecos tester)
There is a thunderstorm going on inside that compressor and if you cut into the freon line, the gas coming out would smell like an electrical fire and the oil would look burnt. If nothing else, they are wasting electricity but if there was any kind of fault in the EGC, you have a hot case or grounding conductors. That is not a good thing in a commercial kitchen where things are frequently wet.