I love the fact how David's squiggle seems to add to the value more than Roger or Chris's.
It maybe reflects his financial situation. The lack of touring over the last couple of years might have hit him harder than the others.
Years ago I bought a ticket for a Gary Moore gig from a punter outside the venue and found that the support act, Larry McCray, had signed the back. I'd never heard of him but I see he's still going so maybe that ticket could be worth something. Weird that the guy would get his autograph and then sell the ticket.