On my Surface GO I have an older generation pen attached, and it sits there fine, it has fallen off two or three times when I have it in its pouch, but it remains in the pouch's pocket so no loss and no worries. I'm assuming the newer pens have even stronger magnets so not even that would happen. The difference is that on the SG the pen is attached to the short west side when in landscape, the direction it is inserted in. But on the iPP I noticed it is on the north long side, and if it fals off from that direction it could feasibly fall out of a pouch like mine. I find it kind of interesting that Apple gets all this credit for design and engineering, but such a basic step as what could happen if it falls of its magnet hasn't been taken into consideration might say more about Sir Jony's design philosophy than we realize.