Score one for the TSA: Security screeners at New York's Kennedy Airport caught a man trying to smuggle a knife onto a flight ... by sticking it in a full tub of mayonnaise. A TSA rep says screeners stopped the man today as he arrived for a trip to Mexico City. The hiding spot was far from a brilliant one: Jars of mayonnaise are also banned from carry-on luggage in the US because the TSA considers mayo to be a liquid or gel. The TSA notes that the man still caught his flight, sans knife and condiment. (More TSA stories.)