Strategery pt.2

In the last tip strategizing post I focused primarily on tips in regards to cash orders. Since that time, I have developed a strategy for shaming tips out of patrons who have used debit/credit cards to pay over the telephone. On a receipt for such orders, which I carry to the patrons door to be signed, there is a total listed--followed by a blank dash for a tip and another blank dash for the complete total. There are three ways, I have found in my limited experience, for a patron to approach said receipt: 1) put a tip in the first blank and an adjusted total in the next--needless to say, I fancy this as the most appropriate approach. 2) put a zero in the first blank (cheap wanker) and the total in the second. 3) Just sign the ticket, leaving both dashes blank. This third approach is the subject for the stategizing session. I opine that leaving both dashes blank, and merely signing the ticket, is the patron's way of feigning ignorance to the proper tip- to- driver decorum. I, for weeks, let the patron get away with this disgusting behavior, but nevermore. Now, I say to the patron, "Would you mind putting in the total in the dashes. This way I don't have to the write the total in my own handwriting--giving an heir of dishonesty" (The dishonesty speil is for my own kicks, I'm trying to paint myself out to be a boyscout trying to get a merit badge, but in reality I'm giving the patron a look like a chessplayer gives his foe, I'm making my move and tapping the timer).I say all this to put the patron in an obvious social quandry. Now, the patron can either put the zero there, and thus win the standoff (which I must say I applaud, it takes gumption to put the zero there while i'm staring a hole through you), or put the tip in the blank. So far it's worked 3 out of 4 times (some punk, pimpled face, teenager got the best of me).