If he hard wires it then he voids the warranty and the UL listing. ...
I'm sure you are right. But tell me, how is it you know this? Not guess, not maybe, but
KNOW. But then again, I've never even heard of an AHJ red-tagging a job, for UL violation, for changing out to a better cord.
... I would have no trouble connecting it to a non gfci 240V recep. ...
I'm certainly not against plugging the appliance in to a non-gfi protected receptacle. I just don't see any point in why. Especially since there are alternatives that have very little cost increase.
... Ranges are 240v and often within 6' of a sink
Absolutely true. But this is not a range. This is not a house.
90.1.B, 90.1.C Generally my industrial customers are interested in "cost effective" - not "cheapest installed cost". Safety, reliability, maintainability are all part of cost effective.
You answered his question. If that is all he needs - then he's off and running. And I'm fine with that. But if there is an interest in a good industrial grade job, an opening for discussion has been provided.
ice