Lots of such good responses.
My hair would stand on end if a CB auditor "advised" me to get a gage block, even though such advice is good for a caliper's simple performance check. But a CB auditor should never say "should" lest it be consulting. He is of course free to say "One of my clients has a 1-inch gage block that they use to just do a quick performance check on the caliper before using."
Although I wasn't there and this fellow is not here to defend himself, it seems to me he has some significant issues. Based on what I've seen this was not grounds for a Major. It was grounds for a thorough exploration with the auditee(s) of the caliper use and the process of ensuring the equipment is calibrated and working properly. If this CB had written a nonconformity I would dispute it. In any case I would complain to the CB about him.