Would make sense with 30+ seconds depending on the level of the warning

30 seconds is a _very_ long time driving.

Imagine AI puts you into a separated oncoming traffic lane when visibility is extremely low (a few meters) and then disengages. It might take you quite a while to get out of such conundrum.

Standard autopilot doesn't do lane changes. Enhanced autopilot does, but requires the driver to acknowledge with the indicator stalk.

I know this was just an example scenario and your point is broader, but I'm struggling to think of another circumstance where autopilot is at fault 30 seconds post disengage, as it's effectively just a fancy adaptive cruise control.

How does this work on intersections? E.g. if you have to turn, because straight ahead is wrong way sign for a one way road.

Autopilot steers with the lane you're in. If it's unsure at the intersection, it will force the driver to retake control.

I've never been at an intersection where straight ahead is a wrong way (wouldn't the traffic be then facing you?), but like any cruise control system, it would likely require driver attention.

Autopilot is not intended to be enable and go to sleep. It's simply fancy cruise control.