I don't think slang should be banned as people have a right to speak as they wish that is if they know when and when to use it. Why should it be banned, just because older members of the community can not understand the slang doesn't mean it should go. They could get to understand and know the language if they tried so they wouldn't feel cut off. So it should not be banned however if people do not know when to stop using it and do not know when it is appropriate then it should be banned in classrooms but not outside of class.