Another GC experience-- this one was not me, but a friend. He bought a used Crown XTi6000 amp via the online web site and it arrived promptly, in the original packing. When he plugged the amp in, it worked all right for a few minutes, then shut itself down...and did this repeatedly. My guy called GC and they said to return it to a local store. When he did that, the sales associate looked it up in their data base, and from what he could tell, that had been the story several different times with that same amp; it had been sold, returned and resold. My guess is, when it got returned to a local store, one of their sales guys -- either Beavis or Butthead...it doesn't matter which -- plugged it in, saw it worked, and it just went back into inventory to be resold as a used item. Again and again.
A manufacturers rep told me that what he saw across the country was when a GC came to town, most of the retail music stores dried up and went away. His observation was that in most markets, one decent local store would survive, but that most of the 'mom-and-pops' wouldn't. This is the story in many, many areas of commerce, not just music stores, but the 'vid-19 thing is hastening the inevitable end of much of the retail world as it once was.