CowboySlim's point is well taken with regard to having an active subscription. And testing the device before you go.
Another lesson or two from that article. Somebody at home should always know your general plans - trail head, possible routes, schedule, and so forth. SAR should never have to search for your car, let alone try to guess which trail you might be on. The time SAR spends looking in the wrong places might make the difference between alive and dead.
Hiking challenging back country by yourself isn't always the best idea, either. You could interpret "not activated" as "there was an active subscription, but the poor guy never had a chance to push the SOS button." Bad outcome either way.
