Traditionally, "bridge and tunnel" does not refer to suburbanites from Westchester and CT (who are on average wealthier than Manhattanites) but rather citizens of the outer-boroughs (Queens, Bronx, Staten Island, Bronx). The term is actually one of barely-contained racism and ethnic snobbery, most often applied to Italian "guidos" with thick accents
Bouncers look out for Bridge and Tunnel people like Guido and friends...
People who live in the suburban arears of new York City (Long Island, Westchester, and also New Jersey) They invade Manhattan. They have heavy NY thick accents, are behind in fashion-they think it is still 1990. The girls have big hair and fake dark tans with long fake nails. The guys are typically guidos yet there are also guys who are 35 and still wearing their 1985 Motley Crue attire.
Everyone whos from Manhhtan hate these people. They are beneath us.
A girl from Westchester with a mobster accent and a fake dark tan comes into fashionable Manhattan to annoy hipsters.