Funny. I remember being on Brighton Station last December, and reporting a couple of "dodgy characters" one of which was looking very sneaky and talking in an intense, instructive way to the other.
I remember one had 'too perfect' hair (like it was a plastic cap, all in one piece), and the other was the opposite, weedy and unkempt looking.
Both were Arabic, (and I have several N.African and Mid-eastern friends so call me profiling, but these raised my suspicions). The bill referred me to the transport police who probably ignored it.
Interesting to find that they really do 'walk among us', but clobbering anyone Arabic is nuts. Everyone should be vigilant but leave it to the authorities to take care of business.
Incidentally, there was a track-side fire that afternoon as well, and the line got shut down! That didn't help alleviate my discomfort about those geezers much.