Exactly! Nothing is more annoying than hearing my phone ring when I'm out hiking or skiing.

As noted above, when skiing I carry mine, turned off, in an inside pocket close to my body. If I should really need it, it is there, fully charged, at body temperature. If someone calls while the phone is off they can leave a voicemail message if it is important. If it isn't important enough for them to leave a message, then I don't care if I missed the call.