I can understand why buyers might want to audition, but for when I'm a seller it's a major inconvenience to offer an audition. A trail would be completely out of the question. One of the reasons prices are so low on Audiogon is because as private sellers we do not have to offer the services that a dealer typically provides. It cost serious amounts of time to provide an audition. Plus you'll always have those people who just aren't serious buyers. Why invite them into your house? If someone does their homework, it shouldn't be a big deal not to have an audition.
I guess another way to approach the issue is to acknowledge the market forces at play. If it helps make a difficult sale, then an audition may give the seller the edge they need to get the sale done. Alternatively, a buyer could use the audition as a opportunity to further negotiate the price. Lastly, if a buyer really needs an audition, they could always offer to pay a premium to get it.
I guess another way to approach the issue is to acknowledge the market forces at play. If it helps make a difficult sale, then an audition may give the seller the edge they need to get the sale done. Alternatively, a buyer could use the audition as a opportunity to further negotiate the price. Lastly, if a buyer really needs an audition, they could always offer to pay a premium to get it.