In my experience, that is the remaining honest 1%.
Well, for a year or so, from mid 2016-2017 I was searching for a nice example of an Audio Note DAC 5. I came across some and 90% were fraud cases. It was either totally fraud, i.e. the guy didn't have the item at all, or it was a botched DAC 4 'upgraded' to DAC 5 with non spec parts, usually in Russia. TBH it was a disaster. I could point you to 5 adverts right now that are fraud for Audio Note Dacs. I think the reason they pick on this model so much is it can be 'made' to look like a DAC 5 from a lower model. That and the fact it has been around for 15 years with minimal updates, so lots of old examples passed off as nearly new ones or genuine items.
My view is NEVER pay anyone without a phone call, the old way always works. Get to the stage were you are interested, basic info, then ring them, preferably a skype call with video on, see the unit and ask some detailed questions about it. Ask for a photo with your name on a piece of paper under the chassis edge, that sort of thing. It is not rocket science. Remember, if it is a bargain, it is probably a scam.
Also don't forget, PayPal + Ebay is not fool proof, and will wrangle out of a charge back if you don't adhere to the rules 100%. I am unsure what protection you actually have on AudioGon, probably zero. Bank transfers are the worse way....