As this hasn't been happening (despite how easy it would be for a terrorist to do), the only logical conclusion I draw is that the entire terrorist threat is so unbelievably overblown it doesn't warrant even thinking about when it comes to evaluating personal safety. I mean, how can it not be, given how easy it would be for a terrorist to just stroll in to an airport departures hall with a jacket bomb and detonate himself yet the closest we've seen to this is one lunatic failing to ignite some powder in his shoes and another idiot burning his crotch.
I think the real answer is that you can probably count the number of truly dangerous terrorists in the world on two hands. The rest of the current crop are nothing more than brainwashed amateurs who spend their time wreaking havoc and misery in isolated parts of the world that no normal person would ever have occasion to set foot in. This article from the FT makes a similar point: http://www.ft.com/intl/cms/s/0/ee2a8412-2923-11e4-9d5d-00144...
If I was a black man in the US I'd be much more afraid of looking at a cop the wrong way than being caught up in a terrorist outrage.