It's all about making it more difficult to steal, not impossible.
Also, with a quality ulock (think ABUS, Hiplock, or even a Skunklock Chemical) it will break multiple cutting wheels before they're able to get through (if they're able to get through lol).
It doesn't need to be unstealable, it just needs to be a pain in the ass to steal, so they will move on to an easier target.
Apply flame retardant to hair, very health!