Let me put it this way.
If I were wearing a baggy t-shirt with short-shorts, and if an airline gate agent asked if I had on anything under the baggy t-shirt, I would have just pulled the t-shirt up and said "Hey, look, I'm wearing shorts.".
That would be the end of that.
The fact that the passenger did not just pull the t-shirt up enough to show the shorts suggests to me that she got defiant and argumentative. That might have been the trigger to throw her off the plane.
I wasn't there, but I know what a reasonable person might have done in that situation. Letting it go that far without pulling the t-shirt up a few inches and showing the shorts is not reasonable.
Enough already. How long will it be before atheists are thrown off the plane?
This is an example of the "slippery slope" fallacy. If X is allowed to happen, then Y will inevitably follow. Y is not acceptable, therefore X should not be allowed.
"If 20 year old people are permitted to drink alcohol, pretty soon they will be letting 16 year olds drink alcohol, then they will let 10 year olds and 5 year olds drink alcohol..."
Fact: Drunk 5th graders is not a necessary consequence of lowering the drinking age from 21 to 20.