I will not wear shirts with logos even if they are small. I had a revelation a few years ago at the mall when I was walking behind a group of girls. A guy is walking towards us, and turns around and walks the other way (like he forgot something). When he turned around, the girls could see the logo on the back of the shirt and then got all excited about "ooh, cool shirt on that guy". Funny, it wasn't cool until they could see what brand it was.
I'm kind of surprised at how many people I know will say they don't discriminate, they don't judge people, etc., and not see anything hypocritical about behaving that way. Sure, appearance matters, but how much someone spends on their clothes doesn't equal "appearance" in my book.
The same people who would scream bloody murder about being "ripped off" by a company for any of a million reasons willingly buy clothes designed to have a very short lifespan (so no one wants to be seen in last year's style from <fill in the brand> ) and don't feel ripped off. Then next year they are back for more. The logos get bigger and bigger until you are paying top-of-the-line prices to be a walking billboard.
I feel bad for people who feel they have to play this game to get the opposite sex interested in them. Doesn't make sense to go out of your way to attract superficial people.