How to correctly plug an iPhone for charge? An Apple official article for iPhone says:


  When you use the Apple USB Power Adapter to charge iPhone, make sure the USB cable is fully inserted into the power adapter before you plug the adapter into a power outlet.


(from iPhone User Guide at https://help.apple.com/)

This seems to hint that plugging the cable and iPhone before plugging both to the charger has some potential risk?  How so?
Looks like basic guidelines when handling electric devices: The moment with the highest risk of anything going wrong is the moment you plug something into the power outlet (or remove it from there). So it makes a lot of sense of not having your expensive device (the iPhone) already attached to the other end.