On the fleet vehicles with these fitted, you turn up the sensitivity lever from 0-3. That basically decides when it activates the wipers in heavy, medium or light rain. The wipers come on at normal speed. If you don't want them on, switch it to 0.
You have manual control between single wipe, off, intermittent, normal and fast.
This sounds like the worst system in the world. Infact I'd question as to whether it even counts as proper rain sensing wipers.
I was just unfortunate that BMW employ clueless idiots to implement their auto-lighting...
Why are they 'clueless idiots'?