Controversially, I think we wait too much opportunity for charity on avoiding free riders.
Not everyone is equally intelligent. Not everyone is equally athletic. Not everyone is equally financially apt. Not everyone is equally generous. Not everyone is equally capable. Not everyone has enough resources for themselves, never-mind enough to share.
Free riders should be considered part of charitable activities. We should give freely to all, not just those humble enough to reject it.
So kick out the freerider! Avoiding doing anything about a problem just because there's potential that some asshole is going to come around is not a good reason to avoid helping others. Some asshole is going to come around and disturb you anyway, might as well help out other people while you're at it.
The problem is that these kinds of things rarely scale beyond a couple of people.
Once you get too many people, you eventually get a jerk who tries to freeride and take advantage of the situation.