If you come up to them saying "how much would you want" you're less likely to get a response than "we raised $50000, how much more do you want?".
Perhaps, but I still don't think this justifies less stringent management. Besides, you can always open with "I know we can easily get $50000, how much more do you want?"
Do you need them to quote a number? If so, why?
I believe that projects like this need measurable attainable goals. Currently it's (appologies for paraphrasing) "If we raise lots of money I'm sure wikipedia will accept bitcoins". I'd like it to be "If we raise $100000 wikipedia will agree to accept bitcoin donations for at least 2 years". The key difference is that with the first there's a very real danger that I'm essentially throwing my money into a black hole, which is no good for anyone. The second one alows anyone to judge if the project was run fairly and achieved its goals.
Essentially I'd like to "kickstarterify" the project.