That announcement was paired with a major lawsuit against a company called Mobile Star LLC. At the time, it was also revealed that 99% of the counterfeit devices tested failed simple safety checks, which obviously rose concerns. Now, Apple has updated its official Apple Support page to reflect awareness.
Apple makes it clear that some counterfeit products, including power adapters and batteries, could be designed improperly, and, as a result, lead to potential safety concerns. To guarantee official parts and accessories, Apple says to visit official physical retail stores, or find a local Authorized Service Provider if an Apple Store is too far away:
“Some counterfeit and third party power adapters and batteries may not be designed properly and could result in safety issues.
To ensure you receive a genuine Apple battery during a battery replacement, we recommend visiting an Apple Store or Apple Authorized Service Provider. If you need a replacement adapter to charge your Apple device, we recommend getting an Apple power adapter.”
Always better to be safe than sorry.