I was a paperboy for many years. I carried 30 papers on my bicycle on a route that was nearly 5 miles long. I knew all my customers by name, and they knew me. I not only delivered the papers, I also collected the money for them.
I've never met my ABJ carrier. I don't even know his/her name. The money for the ABJ is deducted from my checking account once a month. As far as I know, the paper appears by magic. The last time I left a tip in an envelope for the carrier, it got shoved out the back of the tube and onto the ground. I found it several days later in a pile of snow.
I guess the bottom line is that I don't think that my particular carrier is doing anything extra to earn a tip. Perhaps I am being a bit of a Scrooge. And maybe I'll reconsider my position and try again.