The magnets also work great as a way to attach a sunshade.

The magnets work too well. Having one Thinkpad Yoga sat on top of another closed Yoga tricks the sensor into thinking it's in tablet mode and it disables the keyboard. I only lost 30min or so trying to work out what was happening...

There's decent reasons to over-engineer some of these sensors so they can't be unduly tricked by external influences.