I have been using it (Whyte E160).
It certainly works, as I tested it.
It clearly would not stop someone stealing the bike, although it may slow down the process if the thief tried to ride it.
I needed to change my phone & this caused a problem.
Even though I un-paired the old phone (the connection is via bluetooth) I could not connect the new phone.
I ended up taking it to the shop who had to contact Bosch, but not before an identity check that the bike is actually mine.
This all took a few days to sort.
Bosch are clearly trying to make thefts difficult and have a system in place to stop someone connecting another phone.
I'm hoping that the Bosch GPS unit will soon be available and plan to fit that.
The Whyte is great fun, but a very significant investment - protecting it from theft is a priority for me.
Cheers,
Ian