Common sense? What sort of common sense allows you to remotely assess the safety and build of a product? Even if you get a charger in your hand, can you tell?
Can your family? How about your neibhbors? Does anyone you know have this ability?
There is no common sense to be had here. There are people with more specialized information that I have that look into this. There are laws to address this - and I'm pretty sure these laws were written with the blood of folks killed by faulty products.
It's so cheaper that you can buy 2, disassemble one and inspect the electronic (spot thermometer and a cheap ESR tester). it's a charger not a nuclear power plant !