This is what makes the most sense to me, and matches my interpretation of everything I've read so far. I do hope that it turns out like this.
My issues for me personally are two-fold:
1. When on autosteer, I always have my hand on the wheel, but I grip it lightly with almost no torque. Thus, it doesn't trip the torque sensor, so I get the nags.
2. I (nearly) always miss the first visual-only nag because I'm watching the road. The small banner with the blue icon just isn't noticeable enough in my peripheral vision. As soon as I hear the beeps of the 2nd audio+visual nag, I gently nudge the wheel. I have never gotten to the 3rd stage alert where the car begins to slow.
Reading the transcript from Elon, he said:
Something I think will be quite significant is that if the user ignores repeated warning to keep their hands on the wheel, if it ignores the audible alarm more than 3 times in an hour then the driver will have to park and restart in order to enable Autosteer.
The underlined phrase, if interpreted literally, means that the 3-times-in-an-hour count occurs if you
ignore, i.e. do not respond to, the
audible alarm, which is the 2nd nag. To
ignore the 2nd nag, you have to get to the 3rd nag.
So my interpretation is that to invoke this have-to-park-to-reenable-AP behavior, you have to:
1. Either do not have hands on the wheel or grip it too lightly.
2. Ignore the 1st visual-only nag, which will now supposedly be much more noticeable, including white flashing border on the instrument cluster.
3. Ignore the 2nd audible+visual nag.
4. Get to the 3rd nag where the car begins to slow.
5. Repeat the above at least 3 times within a 1 hour period. (Possibly 4, since the statement from Elon says "more than 3 times").
This means to me that within a 1 hour period, you have to get to the audio+visual+slowing level of alert at least 3 times, which should be very unlikely unless you're REALLY not paying attention.