I think it's a bit paternalistic to be concerned about this because of "wasted work". One of the best ways to learn about a piece of code is to start hacking o

I think it's a bit paternalistic to be concerned about this because of "wasted work". One of the best ways to learn about a piece of code is to start hacking on it, regardless of whether or not any changes you make or features you add will be needed or wanted by the upstream project. If someone does the work unsolicited and then complains that you're not merging it, that's a problem, sure. But otherwise, you shouldn't feel bad about what other people choose to do with their own time.