I can see where this would be useful for finding people with Alzheimer’s Disease. They’d be unlikely to remove it, if it were attached to a belt or purse, because they’d forget it had been put there.
I agree, although considering the potential for rampant criminal abuse with something so small and inexpensive as this I think it would be better to have it available by prescription only....at least that would provide some minimal checks against any rapist, stalker, pedophile, pervert, etc. etc. getting one to track potential victims with it.
Let's say that there's a psycho-rapist who takes a fancy to a pretty girl working at a Victoria's Secret shop (like in the recent case of Dru Sjodin here in the USA).. He would only have to observe her leaving work and walking to her car ONCE....now he knows which car is hers. Then, at his leisure, all he needs to do is to attach this device to the undercarriage of the car. Now he knows not only where she lives, but if he tracks her long enough, where all of her family and friends live.
And all of this can be done at his leisure, and from the comfort of his home.
Normally I'm all for completely free markets and as few controls as possible, but the concept of something so small and inexpensive as this being easily available to everyone scares me with the incredibly easy potential for abuse that it provides.