I am not a robot!
Most workdays, I have SO open all day in the background and take time now and then to answer questions. Today was no different (no particular deviation from the usual pattern).
Today, the robot heuristics thought I was not real
Since then I have been prompted to enter Captcha several times (the page with the robot picture).
If there was an update to the heuristics today, the update might be tuned a little too restrictive. If there was no update, I guess I'm just getting unlucky today or something.