I don't see that registering something for guarantee entitles passing on the data to someone trying to flog maintenance contracts
Or, as happened to me only last week, a simple email enquiry to a manufacturer about a power supply now has me subscribed to their mailing list.
Or, as happened to my wife only the week before, school rings up "we're just checking your emergency contact details and don't seem to have your email address or mobile number."
Bearing in mind that not six months ago we had a bit of a barney with the school for passing on our mobile numbers and email addresses to a third party, who then sent us emails and texts pestering us to download their contact app (no, we're quite happy for you to continue sending paper letters home), it wasn't much of a surprise (but it was the cause of much anger) that within five minutes of putting the telephone down, a text arrived from that same third-party company, once again asking us to download their app, and an email arrived encouraging us to "click here to confirm your subscription".
Not only that, but despite not downloading the app (my wife has a "dumb" phone), and not "clicking here", emails continue to arrive from the school via this third-party.
These people just don't get it, and while you might contend that school secretarial staff (other, usually, than one omniscient person) are never the brightest, I see the same attitude time and time again.
I can't see it happening, but I look forward to hearing on the ten o'clock news about the first prosecutions for this sort of thing, come June.
M.