Or use the trick from Java Puzzlers (which may have borrowed it from another source):

Feel free to mail us your feedback written in pencil on a $20 bill.

> which may have borrowed it from another source

Probably Car Talk. Iirc they instructed that puzzler answers be written on the back of a $20 bill also. It was a great radio show!

That is an excellent idea. I hope I'll never have to do that (haven't had to deal with this kind of thing so far), but I'll definitely try this should an entitled user show up in the future.

I laughed at this one, thank you for that