This glucose monitor excuse gets trotted out for these topics every time, but someone wielding a Flipper is probably the least of your concerns if device and connectivity reliability is so critical.
People become inured to extreme risks. It's common to come across people with history of anaphylaxis who only carry one or zero epipens, despite the extreme risk of death.
Some schools ban phones completely. And the school is not responsible if the children can't call 911 if there's some emergency for example.
And some buildings are constructed of materials which will obstruct the mobile signal as well. Nobody is held responsible for that when they can't call 911.
And I believe it's perfectly legal for me to use radio-blocking paint on the walls of my own house, that might obstruct the signals for the neighbours as well, if I'm hypothetically in a weak signal area. In that case the mobile operator has no right to force their signals through my home, it's within my right to block it as long as I don't use any form of illegal jamming.
