[Boatanchors] Random question..

[John Poulton]

A friend asked me a question about a curious little factoid from old TV
shows:

In many Jack Webb TV shows from the 70's'ish, like Adam 12 and
Emergency, they often end transmissions with "KMA" or "KMA367" which is
City of LA's call sign.

Why would individual users identify at random times?
Is this just made up TV usage?

Anyone know whether this was for real?  Just idle curiosity..

73, John K4OZY