Z-list celebs. Hmmm... I'd like to think the organisers deeply regret giving Jade Goody a place, considering her attitude is now seemingly held up as an "example" of a charity runner's approach. Waste of space.
No, the point stands - equating charity runners with a casual attitude towards training and not taking the race seriously is unfair. Maybe you can broadly categorise charity runners into two groups:
(a) People desperate to run the marathon, who to some degree or other begrudgingly go down the charity route to gain a place.
(b) Charity fund raisers who choose the marathon as a genuine challenge which they hope will attract lots of sponsors.
By your own admission, group (a) runners are pretty much like you, .i.e. keen runners wanting to do a marathon, except with different circumstances meaning they're more likely to accept going down the charity route. So no reason either way that they should disrespect the distance. Group (b) people are in it to raise money for a charity. Chances are they've chosen to run a marathon because it is a genuine challenge, and more likely to make people put their hands in their pockets than sitting in a bath full of baked beans, a sponsored silence or a Race4Life.
Why wouldn't these people prepare themselves just as well as any others for the task ahead?
Anyway, cracked record... get quicker and claim yourself a GFA place or go and do another marathon. 