As far as I can tell, at least as far as those Auctions I have won, Gunbroker has about the same percentage, if maybe even less of a percentage, of Bad Apples, as doing Business in daily life does.
e-bay, is about the same in that way, as far as those Auctions I have won, where in my experience with both, if anything, I have found far fewer scammers or cheats or bad-attitude sellers there, than what is usual for trying to do business in person and in daily like.
If considering to bid on Arms listed on Gunbroker, of course look at the images very carefully.
Request more images be added to the Listing, or, e-mailed to you directly, if wishing for further details to be shown.
e-mail the Seller with any questions about condition, timing, lock up, bore, serial numbers matching, etc.
Review the Seller's Feed Back, what kind of feedback it is, and note whether the Seller obtained the Feed Back as a Seller, or, as a Buyer, or both.
Try and get a 'feel' for the Seller's attitude and interest in the item, the seller's ways of doing things, ways of communication, directness, clearity, powers of observation, responsiveness to your questions, etc.
Many excellent Guns get listed by indifferent, uninformed, casual, bad-attitude, chip-on-the-shoulder, or inexperiences Sellers, who do not take decent images or describe the item informedly, so, some listings will have merely one or two crappy, badly lit images, and, a terse incomplete and often incorrect description, yet, it is an excellent Arm, and, may go for a bargain too, being so badly listed.
It is all a matter of judgement, powers of observation, and, intuition even, to evaluate what is being presented, and, the countinance or bearing of who is presenting it.
Many sellers simply will not or do not reply to questions, for reasons unknown, whatever the actual condition of the Arm or quality of description is.
Calculated risk taken as a buyer, is just that. It can pay off very well, or, not, also of course.
Some of my Gunbroker winnings were just that - a definite calculated risk.
Seller merely has a short superficial listing, a couple bad images taken at an angle from four feet away in dim light, Seller having no prior FB or very low FB, Seller did not reply to questions, and...
Usualy, I will "pass' on Listings like that..! Lol...
But, a few times, I thought to myself " Let's give this a try anyway", and, I would bid, be the only bidder, and win.
Seller then communicates, apologises for not replying to prior in house e-mails, says he was out of town, inherited some old Gus and does not know much about them, he then ships the Armn same day as my Money Order arrives, Arm Arrives, in fantastic near minty condition, perfect mechanically, well packaged, and, I am very happy, and won it for what would have been the price for a real 5th rate beater of that Model.
If interested in anything over a couple hundred dollars, I would say, always communicate with the Seller while the Auction is running, establish some history of communication in which to evaluate the whole and the Arm, and, to have that as a basis also of course, should one win, if there is then any disappointment once the Arm arrives.