This weekend I configured one of these in an outside location and was not pleased with the results: 1) The mount is not secure - anyone could simply pluck it off and walk away with it. 2) Is this unit really weather proof? The battery compartment does not look sealed. 3) It was continually detecting motion where there was none. The controlled lights went on probably 30 times in one night when there was nothing in view.
Motion sensor performance depends on location.if exposed directly to light, facing trees/bushes etc, performance can suffer.
In regards to mounting, unless you come up with a way to prevent theft, most sensors can easily be stolen. All mounting options are designed to easily access the sensors to replace batteries which means easily stolen.
I position my Sensor II’s outdoors under an eve for partial protection from direct exposure to rain which seems to provide enough protection but didn’t realize they weren’t indicated for outdoor use until recently when Smarthome replaced one for me under warranty. I have to direct them downward until they don’t pickup street traffic to reduce false alarms. False alarms aren’t unique to Insteon, I have the same problem with my Nest and Arlo Pro cams. I agree the mount is not as stable as I’d like. In strong winds there is enough movement of the sensor to trigger movement. I do prefer the original motion sensor for outdoor use for these reasons.