I can confirm there is no angle sensor on these bikes that cuts the engine. I have had a stationary drop on the F850GS I used to own and the engine kept running.
I would assume the offroad origins of the GS preclude it as when riding off-road you could bank the bike over and cause the engine to cut off unexpectedly.
Personally, I've never been offroad riding whilst routinely banking my bike over 90 degrees and cursing it for cutting out!