Here's what happened:

I had an evening meeting. The parking lot of the building has a
couple of basketball goals in it, and people play there after hours.

The lane with the makeshift basketball court is the inbound lane, so
I had to drive cautiously to allow a man and his son to stop playing and
get out of the way of traffic. They finally did, slowly and reluctantly.

After the meeting, I found a note on my van, scribbled on a deposit slip:

"Next time don't go down the isle people are playing on and slow down."

My guess is that he found this to be an great teachable moment for his son:
Don't stop playing in the parking lot for incoming traffic; make them get
over into the outbound lane and go the wrong way.    And 5 M.P.H. is fast.

Of course, the reason I smiled is that he thought they were on a small island!