If you just want a banjo to play you can buy an identical banjo sans autograph for a lot less money. The whole point of this excercise is to raise a good thick wad for a deserving charity, much thanks to Pete for doing it.
There are a squillion more excellent banjos in the world than there are banjo players - I know, I think I've played most of 'em! Many good players are also collectors and a stash of 40-50 banjos owned by one of these is a lot more common than you'd think - one of the reasons for the high price of collectable banjos, I suppose. Banjos are capable of having a much longer life than people, just because a banjo gets hung on the wall for seventy years you can bet your Fairbanks that one day it'll get loved and played.
Cheers
Ray (who won't be bidding because he doesn't have a good enough singing voice for a long-neck).