It's a fascinating idea. There is the Eternal September effect that can be combated by having a barrier to entry. Metafilter has $5 registration, stack-overflow has their own sauce. My friend who runs the VMS company prgmr.com requires someone to give them a public key to sign up.

I generally think this is a good idea to keep the riff-raff out. (then again, I've done countless anonymous spelling, format, and grammar corrections on wikipedia - but some people say their convoluted markup is the barrier)

The point here is, if I can get my eyes on the prize (the privilege to post), and if it doesn't look terribly valuable - then I have very little motive to hop on board.

My core contention is that the barrier has actually been placed too high. $5, a public key, learning wiki markup, providing correct answers - these are all easy tasks of very little effort. Doing code comprehension and diving into a project - that's a fairly large commitment.

Am I to be held responsible for the code? Will the people behind the project care if I continue to submit after I get the prize?

I count the circle of people I listen to, respect, and care about (here, it would be the commenting accounts) as greatly outnumbering the circle I'd want to work on code with.