Seems like a reasonable approach to me (since it's the one I normally use), although I try to make contact every day or three. As my wife and father are two of those who just KNOW I may have just been run over by a logging truck, I understand the desire to make tracking automatic and easy for family. Nevertheless, I don't see feel the need to feed their paranoia. The last thing I want is a phone call when I've got gastric issues asking why I haven't moved for the last 30 minutes, or calling the sheriff because I stopped for lunch a nap at an overlook with no restaurant showing on the satellite map.