Buying Used Speakers

Want to get the group's thoughts on buying used speakers.  The value proposition in many cases is compelling.  However, there is a pretty good element of risk as well, even from reputable Audiogon sellers.  What exactly does, "completely tested mean?"  Or "performs flawlessly?"  You don't in most cases get a warranty for starters and you're at the complete mercy of the adds and pics.  Some of the sellers are broker dealers (with stellar reputations), so do they even know how they were treated?  Prob not.   Let's face it - the vast majority of condition ratings are based on the cosmetics IMHO.  

Has anybody bought expensive speakers on AG or elsewhere?  What questions did you ask the seller to help ensure they're as sonically good as cosmetically?  Did you test them yourselves once you received them?  Any good lessons learned would be much appreciated as well.  I know for starters to get a complete  description of how they're going to ship them.  Thanks in advance!