I've worn a keffiyeh (or shemagh as they may be better known) for keffiyeh for several years. I'm very in favor of the symbolism behind it and its also a very nice piece of clothing regardless of what you're doing.
I've seen keffiyehs catch on with hipster kids (though the trend seems to have largely skipped Los Angeles) and was a brief flash in the fashion community so they aren't a completely unknown piece of clothing where I live. That said, I've gotten a wide variety of different responses but most have been positive and I'm wondering what other people's experiences have been wearing one or just what your impressions are when you see someone wearing one.
I am as direct as a T-Rex with 'roid rage and about as subtle. It isn't intended to cause upset, I just prefer to talk plain. There are plenty of other people here who do the nice, polite thing much better than I can. I'm what you'd call a "problem dinner guest."