Sal,
As a former waiter/bartender and former restaurant manager, it does not suprise me that someone decided to put this in print. In my experience as a waiter I 'might'

have used a couple of these. However as a manager I learned that most of these scams are already printed. I found all of the ones mentioned in the article in my training manual for Loss Prevention.
The notion that the managers need to 'learn' the scams is proposterous. Most managers started out as waiters or bartenders. They already know the game. More than that, they were probably better at it than any of the employees who are trying to pull these scams.
Flip
Note: Even though at the time I did not believe that 'forgetting' to ring in a soft drink at $1.75 (which had a cost of something like $.08 ) was stealing. I now see the errors of my ways. Just so you know 2 soft drinks with tax will be $3.75 cash only, no receipt.
Flip
"Beer is proof God loves us, and wants us to be Happy"
-Ben Franklin-