Seems like a failure in pacemaker design? The pacemaker kill switch should simply need much stronger magnets so there is no confusion between mobile phone or the kill switch key.
And people are using them anyway.
I understand that the current design was made in a different world, but that doesn't mean that pacemaker design is supposed to stagnate. It definitely can and should be hardened to take into account modern environment.
'simply' here is code for 'will require changes, perhaps significant, to therapeutic processes and medical infrastructure in hospitals and other medical facilities across the planet'.