Leon wrote:
....
No obligation on the cover of the box does not assure me that I am not going
to have to do something to keep from being obligated. I personally would
have rather not had to even open the box to find out any details at all
before I threw the contents away.

You don't ever have to...as the info posted from the USPS stated,
any unsolicited material is not encumbent upon the recipient in any
regard by law. You can trash it or simply write "Refused" or other
indication on it and leave it for the mailman. If somebody else takes
it instead, no problem.