I agree completely. Had I been in an airport in Chicago, New York, LA, etc. I doubt I would have gotten my knife back. AT that particular spot in the Salt Lake airport, there was a mailbox right at the security check-in. The thing that impressed me the most was that, once the security supervisor took my knife out of the little dish, I never touched it again. I had already gone through the metal detector, etc. so she couldn't give it back to me in case I decided to "make a break for it". I handed her the stamped, addressed envelope. She put my knife in it and dropped it in her mailbox. She wouldn't have had to do that for me just 'cuz I was an idiot and forgot to pack my knife and then was absent-minded enough to actually put it in the little dish.
The TSA (or at least that particular employee of the TSA) made brownie points with me that day!