So I was just thinking out loud, and thought for some it may be useful to have a summary on the different presence/location options.
This isn't an exhaustive list, just the ones I've tinkered with, so feel free to add more... All of the ones below require cloud services. Obviously you can also do things at the local level like SmartThings presence sensors, etc.
Life360 - Requires Life360 app on mobile device and the Life360 integration on Hubitat.
IFTTT - can setup an IFTTT applet that then sets a Hubitat virtual presence sensor ON/OFF (requires custom virtual presence driver that supports switch capability). Possible triggers are location (GPS), Life360, etc, etc. Requires an IFTTT account, IFTTT integration on Hubitat, and a virtual device.
Alexa location based routine (currently US only?) - New capability in Alexa app to support location based arrive/leave triggers on routines. Requires Alexa app and Amazon integration service on the Hubitat hub, and a virtual device.