I've heard that joke a few times, but it's always with a different agency... I always have my ASP (expandable baton) on me. Most cops carry their night sticks with them everywhere they go. You honestly never know when you're gonna need it... Traffic stops are one of the most dangerous things we do. You really never know who you're stopping. Could be grandma or it could be someone who just murdered grandma... Tim McVeigh the Oklahoma City bomber was caught by a cop doing a "routine" traffic stop...
I guess I just thought of a night stick as something a cop on a walking beat would use.
As far as traffic stops you sure are right about that. There are lots of cops that have been blown away on traffic stops. Several in my state.