Frank Krygowski wrote:

I'm safety chairman for our bike club, and I occasionally say something
about those members who refuse to say "On your left" when passing.

And on group rides, I'm always trying to keep a mental inventory of who
is where. But one guy is amazingly unpredictable. One day, he snuck up
on my right (where the mirror couldn't detect him) and passed me quite
closely. I chewed him out mildly, saying that first, he probably
shouldn't pass on the right; but if it was really necessary, he should
at least call out "On your right."

Within ten minutes, he passed me again, elbow to elbow on my _left_. As
he did he called out "On your right."

Some people are just uneducable.

e.g., whoever invented a safety message that starts with two identical
syllables, regardless on which side the obstacle is to be expected, and
which, to the uninitiated, does not indicate if the core content
(left/right) indicates an obstacle or the safe direction.

When your driver needs to perform an emergency maneuver into the cornfield,
you certainly would not want to point at the large tree next to the road and
shout, "Now don't you drive into that giant tree!"