I hate those people who walk around with pants down and boxers showing...My black friend said that it is disgusting (his dad is a doctor, his mom is an accountant, so he is upper middle class) another friend said that boxer showing was a sign from runaways at San Monica that they want sex for $$. (Not sure, but he read it somewhere)
I have consistently heard/read that the droopy pants look came from prison culture, where “bitches” ready to “give it up” signaled their willingness by wearing the top of their pants in that fashion. One other variation is that it stems from jail, where they take belts away to prevent their use as weapons or for suicides.