There’s basically zero risk for these cell phone batteries outside of freak accidents, speaking as someone who who’s been building packs since pouch cell Lipos first started coming out for model airplanes back in 2008/2009.. That’s because in a single cell configuration, there’s no way for the charge controller to run up an imbalance and overcharge one of the cells.

I somewhat agree with you. As my last comment suggests, I have a lot of experience running phones as AP’s including phones with dual cell configurations.

Where things go off the rails is situations where extreme heat can be present (shoving phone in direct sunlight in window with hot climate is a bad move) another thing they don’t tolerate well and people don’t talk enough about this is deep discharging the batteries frequently. This causes a breakdown of the SEI membrane and makes it so future recharging generates more heat and gas. This will cause expansion and might cause a short/failure if poorly designed (galaxy note 7).