Along the lines of the above discussion, many mongers go in with the attitude that "I'm the Man, the ladies know how I roll" and figure that it's fine to wait until the end to settle up based on what was provided.
You'd be surprised at how many skinflints and outright scamsters we have in our brotherhood!
I'm talking about going in and creating big expectations of a good tip, for example getting a complete TS slide show with all the trimmings, and then just opt for an HJ back in the room and cough up an accordingly small, pifulous tip.
Or, handing over a big wad of ones and fives as the tip and walking out. Save your F'ing cookie jar money, cheapskates!
Or, I heard about this once: handing over a stack of five bills with a $20 on top, a $20 on the bottom, and five $1 in between. Looks like $100 in the low lights, but once the asshole is gone it's only $43.
One spa I visited recently had a "$50 bill" taped up on the wall of the break room that, alongside U.S. Grant's portrait, bears the printed warning “For Motion Picture Use Only”.
So, yeah, when this shit is pulled on the ladies once, twice, several times, they do get less trustful and might even do a quick count out. I save them the trouble by splaying the bills apart so the denominations can be easily seen and quickly counted.
IANLB, I believe that it is safer to use hand signals to indicate what is desired rather than spoken words.
Just playing dumb wastes everyone's time and can easily lead to a disappointing experience.