[davycro]

Implantable defibrillators are designed to be stopped by a magnet. This is a critical safety mechanism to stop a defibrillator that continues to fire inappropriate shocks. Any emergency department will have a special magnet just for this purpose. If anything it’s kinda cool that the iPhone can achieve this.

[brundolf]

It's important to know about though so you don't toss it in your shirt pocket