Anchoring Into Metal Studs

The main time to be concerned is when hanging the drywall. All it takes is one errant screw to puncture a wire and embed in a metal stud... and it's good bye appliance man or whoever is the next unlucky person to enter that building.

IF the wiring is installed properly, a screw shouldn't be able to pierce it. If you read the article, they weren't. It's probably something that should be checked before the install is signed off.