Buying used or sight unseen speakers a bad idea?

Buying new is a far bigger risk than buying used. If the new piece does not live up to expectation you take a 30% hit. If you buy the used piece at the right price you are out shipping cost at most. Case in point - I have gone through 4 pairs of high end speakers over the last decade and written off a grand total of $500. Most I used for a few years and resold for what I had into them. I only got screwed once in a decade buying and selling on A'gon (on a cheap cable). Folks here are extremely reliable - look for sellers with feedback. Another piece of advice. Stay away from the very esoteric stuff, no matter how good a deal you get - very hard to resell if you don't like it. Better pay 40-50% of MSRP for say a pair of cardas cables than 25%-30% of MSRP for a garage operation brand. The cardas will resell in a heartbeat, the garage brand you may get stuck with.

Now, buying on Ebay is a different story.....

My advice on buying used speakers: buy local or make sure that the seller has the original boxes and foam packing. Only buy from someone with good A'gon feedback who either posts pics or emails you some. Good communication is a must. If a seller really wants to make a good honest deal, you should not be waiting around for a response to your email.
I bought my last pair open box from audio advisor, I get a full manufacturer warranty and they were half price. I'm thrilled with them. There was some hidden damage, but audio advisor took very good care of me. My experiences buying from A'gonr's has also gone very well. The used amp I bought started blowing rail fuses, but worked flawlessly for 6 months before that happened.
I cannot stress enough the importance of having the original packaging with the original foam inserts for heavier equipment. The box my pre-amp was in got practically crushed by UPS. Not really the sellers fault, he told me he didn't have the original packaging but would double box. He did, also wrapped with bubble wrap and filled with peanuts, which probably saved the unit; the box looked like it'd been run over with a forklift. the foam inserts would have better protected the pre, which was luckily undamaged.

Yep, there is a set of large speakers for sale on Agon right now that I emailed the seller about. This seller has a zero feedback score. It's been two days and no reply to my email. I'm really interested in that model speaker, but this doesn't look good.

Not much to add. Just to say it again - never from people with 0 and perhaps only 1 feedback unless someone you trust reasures you that the person can be dealt with safely. Not even if the speakers are free.
Even better approach. Buy only from those who participate here and whose posts are at least okay with you.
And, yes, unless it is something very rare and unique, or virtually new, never pay more than 50% the retail plus shipping.

Maybe I'm missing the point but isn't most everything sold on Audiogon "sight un-seen”? I live in the Chicago metropolitan area, point being “lots of people”, but whenever I have $$$ burning a hole in my pocket, I rarely find what I’m looking for locally. Everything I have was purchased on Audiogon, “sight un-seen”.

Here’s the proverbial local rare exception… I’m right now chasing a guy in the Chicago area who has listed what might be a too good to be true cable (emphasis added)… the only payment option identified in the ad is “Money Order”… and the member has 0 feedback. As fate would have it, the seller has failed to respond to my E-mails. In this case, I would not buy the cable "sight un-seen", and I'm close to taking Kira's “ten foot pole” advice.