I'm a big camera dork. My wife wants to kill me, of course, but I love the old Canon and Nikon rangefinders. In fact, some of them — or at least the optics — (mostly for esoteric engineering reasons) are better than the lenses modern cameras.
I found a good list regarding the perils over here. Most of this stuff is true. If it says "untested," you better damn well wonder why this thing that the reserve price is set to something reasonable, if he doesn't actually know it should be fixed to multiply its value. Most people aren't this stupid.
Don't be stupid yourself. Being a good eBayer doesn't mean you have to be a sucker. Be fair, be square, but don't get cheated.
Most sellers are reasonable people who will compromise to keep both sides happy.