So how will that work? As soon as you turn your phone back on, the mobile network needs to work out what mobile transmitter (tower) you are going to get best reception from, and then route any calls to that transmitter. This was first and foremost a technical feature required to make any cellular network function properly. And warning you that you have moved so that you appear to be in another country where you could be subject to higher call rates seems to me to be a service, nothing more.
You are, of course, quite right - but my concern re. the messages is more the intrusion into an otherwise peaceful day. I'm not that bothered whether "they" know where I am, I just don't want my phone giving me
any info, until I've sat myself down, with a beer, and am ready to engage with the world at large (briefly, and on my own terms). Sorry for the confusion !
(If I use the phone to call an ambulance, the fact that it lets them know where I am is a useful feature, methinks)
However, on the subject of privacy...
To quote Walter Starkie's "The Road To Santiago" published 1957 (chapter 3) :
"...In the past, when life was not so complex it was easier to retire from the fierce struggle and change the active life for the contemplative, many of the greatest thinkers retired to the cloisters where there were none to disturb their meditations; but today our duty to the State and our responsibilities forbid us to renounce the burden of life in the world, and we bring up our children in the idea that it is selfish and unpatriotic to relinquish obligations and retire from the struggle. The tyranny of State and Society will, however, soon deprive us of all the individual's greatest rights. We must live amid the noise and shouts of the world and our houses must be open for all the world to see. Soon we shall not be allowed to possess a secret room closed by a hidden key, for then the guardians of law and order will cry out that it is Blue Beard's closet. "He is the cat that walks alone" they will say, "and we are sure he is a suspicious character." And yet there was never a time when humanity needed so much its moments of silent meditation....."
Apologies for the length of the quote, but I felt it relevant