I confirmed it with support.
They turned off the motion sensor (PIR) changing the state from Away to Home.
IF you were using Auto Switch, which using geo fencing, that still works.
BUT - the motion sensor on the thermostat is essentially disabled.
It will “resume schedule”, though I’ve yet to confirm what that really means.
I would like to add my support to having this allowed again. The solution is not to delete the option entirely, a reasonable solution would be to make it a setting that is disabled by default, but can be intentionally re-enabled by those who like and want it. Worst case scenario leave a disclaimer when the setting is enabled that tells the user that enabling this option may present “false detections” as people were complaining about it, and “if you experience this, please just disable the option.” and tell support to repeat this in their scripts or something. That is a reasonable option.
At the very least, they could enable this in the rules so people have to intentionally set it up. Or it could then be linked to other sensors (motion/contact sensors) to change the state. The thermostat will be getting satellite motion sensors for it soon, and this is definitely something that should be allowed from a motion sensor specifically designed for the thermostat, otherwise it’s almost pointless to have them. Maybe those will have more reliability too. Regardless, it should be up to the users to decide if it reliable enough for them to leave it enabled or not, not take away the choice.