I can definately understand your anxiety around that; particularly since at least half of the idea behind the spread of copybot crap is to blur the lines between legit and stolen free content.
That said, I have no idea what to do about that. Once you release something "into the wild" it's out there and a lot of the point of open source is to allow modification. If you don't allow modification, then you block people trying to learn as well as folks wanting to "stir the pot".
My best -and only, answer is to figure out a way to have an authoritative source; "if you get X from here, it's good; if not -well, don't be surprised if it's crap". That's essentially what Firestorm (and other viewers) mean when they tell you to only trust downloads from their site (ignoring self-compilers for a moment )..