It looks like you install it by tightening it with a wrench, which expands the rubber anchor. Basically, sure, someone could come along with a wrench an loosen it. Or, just cut your strap with a knife. Isn't the basic idea to make a thief think twice, and to send him on his way, looking for an easier goal?
I don't think I'd use this for my future Enertia because one of my favorite mods is the bar-end mirror.