My guess is some reactionary, standing-up-to-the-man activity like squatting in a vacant property - all as a political statement, of course - the fact that it saved on rent for six months is coincidental.
Certainly no reason to be classed as terrorist.
Mind you, judging by his attitude to .. um .. anyone else, I'd say that he should be classed as obnoxious a**hole.
What I find most ironic is the personal level of his spite to TSA workers and the way he seems to think that he is the one who "wins" each time he meets one.
Whatever the case, he is just another attitude-laden loser whose journeys are made that little bit more stressful because he thinks that his "political" opinions trounce the laws of the land (be they right or wrong) pfft.