I also donate big, when I think the cause is really worth it. :)
But, you left me curious...
Does he usually ask for donations?
And, if so, does the money go to pay for his expenses, or does it go to the
FSF?
(I always had the impression that the travelling, accommodation and other
expenses, in our "rich" Western countries (I'm not sure if that's your case,
also), are usually paid by whatever is the organization that invites him, and
that the GNU auctions, at the end, are just some extra money for the FSF...)