A tea leaf could somehow start the vehicle and drive it back and forwards, but that's about it.
In the thick end of a decade on a autocrime team it was the only device that featured in attempted theft reports with a 100% success rate. We've seen all sorts of locks and gizmos and someone managed to get past all of them at some point, but never a Disklok.
As aforementioned above, we'd often see home cctv footage of scumbags walking up a driveway at 3am and eyeballing a disklok and shaking their heads and walking away, usually without even laying hands on the vehicle. More often than not they'd help themselves to something similar close by that was unprotected.
And no, I do t work for them or have any affiliation. It's simply an item I have great professional experience of being highly - in my dealings 100% - effective.
Aye, anything more than a very thin cover is going to render one useless. Disklok to actually sell a sort of steering wheel condom to protect the steering wheel from damage by the lock, but in need two decades of using them myself I never damaged a wheel so never bothered.