First, a PLB and SPOT are two different devices which operate differently. SPOT has the ability to send a "Help" message (to friends or family, etc.) as well as "911" (a Distress alert). There is no "etiquette" or standards or specific law with regards use of SPOT. I imagine that local and state laws related to false alerts and the like will be held applicable if it is abused. A PLB is legally supposed to be "used only in situations of grave and imminent danger." Obviously, this is subject to personal interpretation and can vary. What I find "grave and imminent danger" another person may not consider as such. An 80 year old person may find a situation a "grave and imminent danger" when someone half their age may not. This has been the situation for many years with all 406 MHz beacons and it has generally not been a problem. The bottom line is that authorities will consider a PLB distress alert as one where life is at risk and will respond accordingly. By and large, I'd expect the same will be the case for a SPOT 911 alert.

However, we already have had a case where an SPOT inadvertent false Help alert (unit turned on inside a pack) turned into a distress response when authorities were called by the alert recipient and only a last minute discovery by the SPOT user that the SPOT had been set off allowed him to cancel the alert with an OK signal. That is one possible advantage a SPOT has, but it was a design failure that more easily allows such alerts to be sent out inadvertently in the first place, compared to the PLB which has design standards in place to help prevent such things. This is a classic example of why SPOT's "Help" alert capability isn't quite all it's cracked up to be.