I remember back in my university teaching days, there was this one guy who was a total cheesewad. He'd sniff around the high school parking lot on Friday nights if you get my meaning. He ALWAYS, ALWAYS, tried to play the pilot card too.
So one night my buddies and I decided to sabotage him good. We went to our usual hangout bar for an evening of booze and foosball, knowing that eventually this guy would show up. Shortly after we arrived, a large group of ladies entered the bar and we knew that each and every one of them would be his type (ie, they were breathing). So some of us went over to them, real serious like, and told them that there would probably be some guy in here later tonight that would try to pick them up by claiming to be a pilot. We also said that he would try to impress them by showing off his liscense (since he was a CFI, he preferred to show off his instructor ticket thinking it was more potent). We informed the ladies that he would be showing them a FAKE liscense and proceeded to show them what real liscenses looked like, by pointing out the blue DOT insignia in the corner and telling them that his could probably have a black one since it's a fake copy. After this spiel we casually walked away without further bothering them.
About an hour later, sure enough, the guy comes in. Shortly after getting his beer he heads straight for this same group of ladies. True to form, he whips out the CFI cert and lays on the pilot rap. The girls all looked at eachother in disbelief, as if to say "holy crap, those guys were RIGHT," and told him in no uncertain terms to get lost. Several drinks got spilled in our area as a result of the roaring laughter we suffered over this event.
Oh, and on the rare occasion that a lady asks me what I do for a living (I never offer the info myself), I reply modestly by saying "well, you'll probably think this is a cheap pickup line, but I'm a pilot." I only show the cert if they ask to see it, and that's not very often. In my experience, ladies are thoroughly unimpressed with a guy who is a pilot for two reasons. One: they don't believe the guy actually IS a pilot or are very turned off when the guy tries to hard to prove it. Two: they live in an area, such as a town with an air force base or large flight school, where pilots are a dime a dozen. Now by this one I am in no way downplaying military pilots or the students/faculty at the school, I'm merely saying that the ladies would not be impressed by something that is so common to them.