Budget carrier Spirit Airlines quietly updated its contract of carriage Wednesday to include a more thorough dress code — which caught at least some unsuspecting travelers unawares. The new

Spirit Airlines has revised its "contract of carriage" to include updated guidelines for passenger conduct and attire.

The airline clarified (somewhat) the attire and appearance that might prevent passengers from being allowed to board or remain on a plane, a move that goes a step further than other major U.S. airlines.