No problem (Score 2, Insightful)

You've gotta pay people to work on deadlines sometimes. I've done volunteer work which has led to paying work, driven by nessecity. Most volunteers have day jobs, and aren't extremely wealthy. If they're being asked to put in a lot of hours, it's only fair to compensate them for the time they can't spend working at their normal job, be it freelancing, a normal desk job, or whatever.