True. It’s surprisingly effective, though. Another route is to fish around for their return envelope and send them a pretty leaf or whatnot, but that could just spur them into paying more attention to you.
I used to gather up the credit card application forms for Brand A and mail them to Brand B in their prepaid envelope. I did so many times that Citi finally send me an intimidating letter from their fraud department asking me to stop. I didn't, of course, but they eventually phased out the prepaid envelopes altogether.
Yep, as a last resort I tried doing this with an apparently unstoppable catalog and got about a month before the postal worker scrawled a nastygram back on one threatening delivery embargo.