Bob
Thank you for clarifying your post and making you position explicit.
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If you are out in the wilderness, SOS may be the only way you can call for help. If you use SOS and later decide that you don’t need SAR, “Cancel SOS” may be the only way to communicate this. Why you sent the original SOS and why you changed your mind are irrelevant. What the sheriff should do or will do upon receiving the “Cancel SOS” is irrelevant. What you think the sheriff will do is also irrelevant. Sending the “Cancel SOS” is the best you can do with no other means of communication.
The concluding sentence is precisely what I consider irresponsible. Having a Spot with a cancel button does not make the Spot to only means of communication available. If the situation was significant enough to require calling for a SAR then it's worth doing whatever it takes, including hiking your butt to a trail head and getting into communication with the applicable authorities to close out the response. And you are right, that doesn't depend on why the call was made or what the sheriff has decided to do. Whoever made (or requested) the call bought into that responsibility when the call was made in the first place. I don't think the rules are different for people with cell phones or Spots or schedules they would like to keep. I believe that is what responsibility requires. I'll be whatever that makes me to those who suggest that the new technology removes the need for responsible behavior if it isn't as convenient as their new toy.
saltydog, that's my "Discuss."
Dale B. Dalrymple