I just got the boys chipped two weeks ago. I feel better.
It is not fail-safe. Like you all know, someone has got to FIND your cat. If they just disappear...well, it's better that nothing.
What I'm waiting for is a tracking device, possibly on the GPS system, where if your cat goes missing you can find his location. (I suppose if this were possible, they'd to it for those 'fur-less cats' (kids))

We could use it in case of fire, when the cats go in the closets.

Please, someone invent that.