Back before I knew any better I listed and gave away two bikes I had found on the trash pile and had subsequently quickly fixed up. They weren't expensive bikes but both were nice and only needed minor adjustments and a tube or two to make serviceable. I politely stated in the craigslisting that I wanted the bikes to go to a good home to some child who needed a bike. Both bikes went quickly to "dads" picking up bikes for their kids.

Two months later I went to buy a bike for myself off of craigslist and bumped into "dad". Now I suspect he got both bikes by having a friend pick up the other.

Live and learn.