I agree but there is the other side of it as well. We've inherited a collection which we are trying to evaluate and sell.
Trying to verify authenticity for buyers assurance and to make for a more pain free transaction. There is a market for second hand which of course carries some risk but it can be done safely.
Believe me I've been searching for information but it does seem to run around in circles. Thanks for everyone's help trying to get this information.
For items of substantial value, I would strongly suggest consignment with Ann’s Fabulous Finds or Yoogis. The cost of consignment has to be measured by the reputation of the reseller (and the wider audience of prospective buyers); the reseller‘s method of authentication; the professional photography, listing, packing, ease of sale, issues of return, not to mention transaction fees, 1099s, etc. JMO, and YMMV
Good luck.