I'd have no problem giving money to someone who intended to do the distance but didn't. It's the people who don't even intend to do the distance who need a thorough pieing.
Gladrags, yes, I saw one bloke on the telly who ran a stupidly fast time (well sub-3) yet when he'd finished he looked like he hadn't even broken sweat. Skinny guy, black, yellow vest, didn't even have a proper number - his just said "Wanjiru" on the front. Cheating b***ard!