I have had two FFl dealers try to burn me on deals from a auction on line. I ended up having help come from the Postal Inspector, LEO and in the end both lost their FFL. GunBroker was absolutely no help at all. It boiled down to using the mail to commit wire fraud. I did get some help from local law enforcement but it was limited. I was a lot younger back then and was much more likely to spend more money and time than being rational when I got pissed off. I have several other guns with defects hidden by careful camera angles or defects not noted in the description. As a rule I will return the gun if it bothers me enough or if it is minor just move along. I just do not have the desire to go off the deep end much anymore. I did once upon a time.
For example, I had a person bounce a check for about $1,800.00, back in the 90's, just before he moved to Vegas. I reached out to a retire police officer I knew who moved to Vegas after retiring and asked him if he ran across the fellow to drop me a line. What he did was make a couple inquires with security for other casinos as he was working at a casino in security. Sure enough my man was working as a dealer in one of those casinos and the head of security called me. I explained I was looking for a person who bounced a check just before moving to Vegas. He asked me to fax him a copy of the check. Yeah it was that long ago. They called him in and asked him about the bad check. He tried to BS them and that was a mistake. They fired the dealer and walked him out of the building. He was deemed a security risk to the casino and they were quick to cut their losses. I did get paid by the casino the full amount of the bad check. I understand every casino in Vega got a warning about him. I doubt he stayed in Vega long after that.
Do what you are comfortable with. Minor things I just write off these days. If it were a major thing, maybe not so much. But if you have documentation I would post a warning for others. Other would not and I understand their reluctance.
