Why do girls have their name written on their butt?

So, I went out with this guy- just once and only long enough to get my food. I met him online and he seemed pretty cool so we met up at a Cafe Rio somwhere between me and him. While there, I noticed he was very observant, so much so that he was distracted from carrying on a decent conversation. About this time, I noticed he was especially aware of a 19 year old girl with fake boobs ready to burst forth from her teeny tiny little tank top and her low slung capri sweats with her name plastered across her butt. He had an exorcist moment checking her out. So, when he completely ignored my question twice, I changed my line of questioning to, "Melissa (the name on her pants) has a nice ass doesn't she?" and he immediately responded with, "Oooooo yeah...whoa, wait...wha?" I stood up, thanked him for dinner, and left him to ogle Melissa and her butt. I didn't talk to him again after that.