I already do this
along the same lines, I read somewhere (possibly here, I don't recall) of some chap who would pick out the most egregious offenders, and send them a small amount of copper coinage in their envelope. He would then wait a few days, and write in claiming that he'd made a terrible mistake, and could he have his 7p back please?

Apparently, it causes them a great deal of aggravation - find the money, clear it with accounts, blah, blah - but the end result was always a nicely-cut cheque for some risible amount or other.

I hope it's true.
( Happy Phantom has been to Hastings, Brighton, and Eastbourne too, Fri 18 Jun 2010, 15:05, 1 reply)

Now this, I like.

( Enzyme is powered by sunlight, Fri 18 Jun 2010, 19:52, closed)