We do some auction unit buying and have a small store, so we have a pretty good feel for what items are worth, donation values, etc.  Then you have the people like Storage Wars, Auction Hunters, etc who represent junk as valuable through seeded items and pre-auction selected "experts".  Example:  Allen and Ton bought a storage unit that had a drum set with a Zylgen Cymbal.  Oh, the "its so valuable" claim.  Took it to some "experts" to sell.  They paid $1500 for the cymbal and drum set.  You could buy the same trap set for $250, including the same cymbal every day on Ebay or CraigsList.

Same with the firearms, antiques, etc.  Every value that I have taken the time to research is inflated significantly on these shows. 

We had Storage Wars Texas come through here recently.  There were some locals for color, but it was clearly set up to sell the units for far more than market to the actors/buyers, with the usual "this item is worth XXX" and "Bob" won with a profit of XXX.  Sure he did.  The only way he made that profit was "blue sky" based on the "guesstimates".