I've been burned in that manner. Not on Gunbroker, but a small-ish reloading forum. A guy ran an ad for two presses and showed a photo of both presses set up with dies, one for .45 Auto and one for 9mm, with several accessories. There was NO disclaimer that the dies and accessories weren't included.
It wasn't an auction, it was a "For sale" ad, and I bought. When the box arrived, there were no dies, and most of the accessories were AWOL. I contacted the seller to ask where the dies were, and he replied that they weren't included, and that "any reasonably intelligent person" would have known that based on the price. Mind you, the ad also stated clearly that he was selling "everything" because he was getting out of reloading.
I was rather (ahem) "displeased," to say the least. What had seemed like a good deal is going to end up being only a so-so deal by the time I buy the dies and other stuff that wasn't there. Just to pile on, many months later the guy is still on the forum and still reloading -- bragging about his new Dillon press.
So he was basically just a liar, and I allowed myself to be fooled by the fact that it was a small forum where everyone seemed pretty much legitimate and helpful.