In the mid 70’s I worked nights in downtown Milwaukee, 5 pm to 12:45 am. I wore a glasses mounted mirror, as I was riding home at 1 in the morning I noticed a pickup coming off a side street and it started following me. As it got closer it started getting closer to the side of the road nearer to me. I noticed a spot up ahead where I could pull in between parked cars and pulled in as it passed me.
When it went by a guy was leaning out the window hanging onto the side mirror with a baseball bat in his hand. Luckily they just kept going.
I will never ride without a mirror.