Poor Golden - if I had received a message like that, I would have been apprehensive too!
As an option I think it's an admirable idea.
My only concern is whether buyers might use this as a means of pressuring sellers in some way. How, I'm not quite sure - but eBay buyers have been creative in finding advantages, so I'm sure there will be something.
If you want such a thing on eBay, just suggest it (as a buyer) in that it could prompt sellers to make offers that result in more sales. EBay thinking will analyse it thus: Buyers spend more, fee income increases: Check! Sellers do the work, carry the risk and bear the cost: Check! We just make a programming change: Check! ... plus we get a new source of glitches...: Bonus!!!
Sounds like it would make the short list for a pre-Christmas implementation.