Has anyone ever filled out cards for art they didn't take?
Yes, at least a couple each year. Even though I have signs posted explaining the concept, both short and long form in two places, some think the point is to comment on the art, like it is a viewing gallery. I get cards saying, "I'd love to take this home". ARGH. TAKE IT! Others think they come back for the art at the end of the week. Yeah, no, that never works out.
Others start a card with the name of the art they are donating, but that rarely works as the card gets separated from the art, or people think the piece is spoken for.