"Code Red" generally applies to any girl who in that particular situation (e.g. The Griffin Inn, Dale) looks quite attractive due to there being a lack of any actually attractive girls in the vicinity. As a result this girl will suddenly find herself idolised and surrounded by up to twenty suitors (posing as a film crew for example) very quickly.
Me: 'Yo, yo! Code Red, over there!'
Pimp: 'Jean Claude Van DAMN she's fine'