Even though a busy airport is likely one of the most popular places to see a lot of interesting people dressed to their full potential in self-expression, some airlines are now calling in the fashion police and refusing to let people board their planes because of how they are dressed.

Recent cases of this newfound airline dress code enforcement involve one woman who says she was confronted by a Southwest Airlines employee for showing too much cleavage on a flight back from Las Vegas, while another woman says that an American Airlines pilot read her the riot act for wearing a T-shirt baring a naughty four-letter word.

The problem with an airline dress code policy is “what’s appropriate” is not clearly spelled out to the passengers, as airlines do not publish standardized dress codes. So, without a guideline to tell us how far is too far, are we just supposed to rely on our common sense?

Kenneth Quinn, an aviation lawyer and former chief counsel at the Federal Aviation Administration seems to think so.

It's like any service business. If you run a family restaurant and somebody is swearing, you kindly ask them to leave.

While this might seem like a First Amendment issue, Joe Larsen, a First Amendment lawyer says that the airlines are well within their rights to make passengers change shirts for anything they deem inappropriate because even though the First Amendment prohibits government from limiting a person’s free-speech rights, it does not apply to rules set by private companies.

Industry representatives say these unwritten policies have less to do with an actual dress code and more to do with respect to others by not wearing clothing with curse words printed on the front of them, watching pornography in sight of other passengers and showing off too much skin.

However, passengers who chose to push the boundaries of airline dress codes may want to reconsider causing too much of a ruckus – being accused of interfering with a flight crew is a federal offense.

Airline representatives say refunds are offered to passengers who are denied access aboard a flight.

More From TSM Interactive