Elephants and rooms etc.
Not everyone carries a phone..
Not all phones are 'smart'
Phones must (usually) be switched off on planes and other signal sensitive areas.
Some environments do not allow phones to be taken on site.
Some areas do not have reliable mobile phone signals.
Phones are often turned off and only turned on when needed
How long before NOT carrying an approved phone becomes a punishable offence?
How long before total surveillance becomes the norm?
Perhaps we will all be compelled to carry an embedded transponder that will determine your civil rights.
Are we looking into the abyss?