I've found that the impact on battery life depends on your distance to a tower. The phones I have used will burn battery like crazy to connect to a fringe or intermittent signal.

The other part is: the last thing I want to do on a hike in wilderness is to hear or answer any damn phone call at all, unless it's someone I know and I think it might be a critical situation. I'm out there to purge that rubbish from my mind. It completely destroys the re-sync, the rhythm, the reset. Otherwise I might as well hike in a shopping mall. My 2c.

I still have to put our phones in airplane mode when we are on the farm in WV or they will keep trying to connect to towers and drain the battery real quick.

The whole not answering the phone thing will be different per person. I was just saying I can relate because I get less than 10 legit real calls per year and 10 or more spam calls a week. Its made using my phone as a phone useless, its not about the time taken, its knowing that any call I get isn't a call I want.

+1. Plus, if you answer spam calls the spammer knows there's a human at the end and you get even more calls. The guy had no idea anyone was searching for him and no reason to answer his phone. I virtually never get a real call from someone not in my contact list.

If the hiker doesn't answer then search and rescue have to assume you require rescuing, and get a team to start a search.
Only answering and saying you are ok is going to get them to stand down.

So not answering your phone causes other people hassle, so if not going to answer regular phone calls, perhaps you should put some effort in.

But how is the hiker supposed to know that? Short of being psychic anyways!

So it seems that SAR should do both.

1) First, call and leave a message if no answer. The message should contain the name of the person that instigated the search. That person presumably would be someone the hiker knows, so the hiker would infer that it is not spam.

2) Also send a text message containing the same info as in 1 above.

This doesn't require any special equipment, and since each action contains either a recording, or text message they should get through eventually (if the hiker's phone is turned off at the time, presumably the hiker will turn it on again and the messages will get through).

Maybe don't give your cell phone out to just anyone and certain no businesses. If you are plagued by marketing calls, get a cheap second phone keep the number to just close family & friends.

Or get a two way satellite messenger.

I haven't given mine out, they figure them out eventually.

Keeping your number secret sadly does not work. I have a number I have never given ANYONE that gets five or so junk calls per day.

Does over here. Have a mobile for family & friends for few years now, and not had a single marketing call on it.

Do not give your private cell number to any business, chance it'll get sold to scammers.