Reductio ad absurdum, wouldn't it be better just to have everyone's phone explode? Chances are pretty good the (alleged) killer will have one on them, so let's just blow everyone up.
If you don't, we'll end up with a murdered child, so why not?
Reductio ad absurdum, why not make all communication illegal without the explicit written consent of the recipient? Then you'll never have to be bothered by anyone ever again.
Is that supposed to be an absurd proposition? Because that is something I want. Stuff like advertising should be straight up banned, and it should be considered abuse to get a phone call from someone you have not explicitly whitelisted, especially corporations and governments.
No one should presume they have an IRQ line to your brain and attention. They don't get to interrupt you with bullshit you couldn't care less about.
Ok, what about an air raid siren? Someone speaking to you on the subway? A letter from the government about an upcoming election? A road sign warning of closures? Someone with a megaphone directing traffic?