How free is free?
This is a potentially difficult issue. That's why we decided that free should be really free. Absolutely free, no strings attached. That's the only way to avoid blurring the lines. Of course, sometimes a grateful recipient may decide to give a small gift to the donor, but there should be no demands or expectations in this regard.
There is, however, an expectation, in fact a requirement. And that is that people treat each other with respect, that they are polite in their interactions, that a recipient shows up when arrangements are made, and that they say "thank you". It costs absolutely nothing and it makes the world a better place.