I have this problem that no matter what it is, any text that passes before my eyeballs gets read, often at a barely conscious level. I can't stop it. I assume many literate people have the same problem. Today I was on campus, and while waiting for the bus and admiring the splendid, ah, charlie-foxtrot that is University Ave. during this construction season, my brain forced me to do a double-take... "numquam tickle?!"
I took a closer look at the book bag: Draco Dormiens Numquam Titillandus, "a sleeping dragon is never to be, um, tickled?" Finally the rest of my brain kicked in, and I realized I was looking at Harry Potter-ware. A college-age male — and not a freshman, I'd guess — was sporting a Hogwarts book bag. He's the right age for it, I suppose. I haven't yet decided if I want this to be an ironic gesture on his part or not.
A little googling tells me was displaying Gryffindor colors, in case anyone was curious.