That thing about the looking Arabic appears to be quite true, from what I can tell. Normally they are pretty thorough and suspicious -- sure, they're not people you'd invite to take with you over to the bar on concourse B but at least they're actually doing a decent job, especially since it's tax money paying them -- but they seem to always triple- or quadruple-check my details every time I have a beard. It was made even worse since for a while I kept carrying around a temporary ID with my real ID, even though it was expired and thus not valid -- when they asked to see it and noted the eye color didn't *quite* match up between the two (who knows, maybe the dude at the DMV the day I filled one of these forms out was color-blind), I kept worrying they wouldn't let me on the plane. Thank heavens I managed to get on in the end. I can only imagine things would be even worse if I decided to bring my "DIY Home Explosives Kit" on the plane with me.
Since I normally don't have to deal with security officers thinking I'm going to blow up a plane with old game cartridges and my cell phone (hey, I like old games a lot and am entirely unashamed to admit it), I tend not to shave. It's just something that doesn't have a lot of rewards for the sort of effort that is often involved in the process. Admittedly it's not a Herculean task, but it does feel a bit like I'm channeling Sisyphus given how quickly it grows back. Besides, I look better with a little hair on my chin and my girlfriend seems to agree so I'm not going to argue with it.
It also doesn't help that the preliminary procedure for doing this is under most occasions to just run a pair of trimmers all over my face because of how long the hair is. Seriously, it's the length of most of the rest of my hair on my head whenever I go over to trim it off. It's certainly more scruffy, but it's not something that one can just take a razor or electric shaver to and trim it off. Sure, they'll result in a closer shave but that is amazingly painful and usually involves a nick or two on my skin.
Here's a way you can see for yourself how bad it is: try to pinch like two or three hairs on your lower arm and rip them out as quickly as you possibly can. That's what it feels like, only it goes on for about half an hour as I try to cut every single damn hair off my face. You can see why I end up using trimmers.
Now, the problem with using trimmers compared to an electric shaver is that there is no way to actually collect all the hairs that it cuts off. They'll end up going all over the sink if I use the trimmers right over it (which I need to do basically in order to see what the hell I'm trimming off and that I haven't missed anywhere), and they'll all be really tiny hairs that are almost impossible to clean up. The only way to get around this really is to hold a waste can (a small one suitable for the bathroom, of course) underneath me right at my chest a few feet from the sink in order to collect all the hairs because it's a wide area and all of them collect pretty well.
One thing to note is that this works significantly better the longer my beard is, since the hairs all collect near the blade and can be sloughed off easily. Since that way I can just brush them all into the can without worrying about tiny stray hairs going everywhere or getting stuck in the drain, I tend to wait until it's reached a minimum length before starting; there's thus a sort of no-go period for shaving between being short enough to be shaved with the electric razor painlessly and being long enough to be easily taken off with the trimmers.
I also tend to do it with my shirt off. That way it doesn't get stuck to my shirt and make me itch all day while I wear it, since they can't be removed at all without running the shirt through the wash or something similarly drastic. If I do it with my shirt off I can either shower afterward or just rub myself down with a towel, which is far more forgiving about these stray hairs than my shirts are.
Of course even then it's still not a perfect scenario and I have to clean off a lot of stray hairs even then. It's a lot of effort and is a major reason why I never even bother going for a complete shave; I've been burnt out enough already, especially since the electric razor (which is actually able to collect hairs inside itself to make cleaning less effort-intense) doesn't work its magic as quickly as the trimmers and, again, has the tendency to be painful and unpleasant. Sure, if I used them more often I'd never grow out the beard to the point of painfulness and wouldn't have the damn hairs everywhere but I don't want to do it now, and I never change my mind on this. I haven't used it in years, I'm pretty sure.
Besides, that shaver irritates my skin a lot, and I look better with some stubble on (in fact studies have shown that women find it more attractive or something I think).
So yeah, I look like a hobo half of the year and that is why. At least, that's my explanation. I'm still trying to come up with a plausible explanation for why (since I rarely shower either) I always smell like one too.