10-codes can be used to law enforcement’s advance in a situation where you don’t have a ear piece, and your lapel mic is where the audio comes out, and dispatch says “Are you 10-12?”, which means are you present with a subject for most agencies. When dispatch says that topically the subject you are with could be a person that you had dispatch run them through NCIC, probably has warrants, or has info that as the officer you don’t want the subject to know that you know. Because you are probably going to have to arrest them in said situation.