I hate to be a partypooper but when I worked full-time in the marketing department of a large charity, we did a study of funds we received from London Marathon runners. Sadly only 10% of runners who declared themselves fundraisers for us in advance actually ever sent us any money...sorry...
It is a much much harder task to get people to put their hands in their pockets than it is to get them to pledge in the first place. I hope the guys succeed, but if I were in finance there I wouldn't bank on getting more than 50% max.