Possibly a silly question, but wondering if the fact that when we query for devices, we get all devices for all locations rather than for a specified location, does that mean that we could potentially create a rule that works with devices regardless of location? Eg if switch A is on at location 1 and switch B is on at location 2 then trigger light C at location 3?
No, it’s not possible because we need to specify in which location the Rule will be created, you can take a look at the API reference where the required parameters are specified: API | SmartThings Developers
So, if you try to use a device ID that is not from a device in the location, you’ll get an error saying it is not found.