The airline can put "inappropriate" in its contract all it wants; my point was that when such a vague, subjective term is used, the airline is asking for trouble. Restaurants generally post "no shoes, no shirt, no service" - pretty clear and unambiguous. In addition to the vagueness issue, there is also the issue of uneven enforcement. Not saying it is a slam-dunk; just saying it raises issues.
According to the article, the only thing exposed was part of his boxers - no allegation of any flesh. Apparently, having part of his boxers exposed bothers some people. Very skimpy halter tops, midruff-baring tops, bike pants, very low-cut crack-revealing pants and other traveling attire that I have witnessed bug some people but are allowed to fly. The list is endless. Doesn't it not smell right that this kid was booted and taken to jail for wearing something that is so prevalent?