I was sitting near them and I watched them, and in fact then the flight attendant came and sat directly behind them, so I suspect that she had conferred with someone, possibly the captain, and been told to keep an eye on them.
They both spoke a fair amount of English, but one of them was probably directly from the ME (he was wearing flip-flops, despite the fact that the weather was cold and wet).
In retrospect, I think it would have been better to have made a fuss, even if it had resulted in a delay. These guys seem to have been nothing but rude and behaving with the usual Muslim contempt for our rules. But certainly, if Muslims see that it is possible to get away with this behavior on that airline (it was operated by some small company as a feeder for a larger line), it will obviously occur to the terrorists among them that this is an easy target.