Talking about counterfeit, I realized that I recently bought a (most likely) counterfeit Renata battery off eBay. Dude had about 1500 positive feedback so I thought he probably sells legit stuff.
Nope. Battery was almost dead on arrival - even though it had a "good by 2025" date on it. Exhibited all the characteristics of a fake battery. Threw it out and bought a legit Energizer from the drugstore.
At least the eBay seller gave me a refund when I said battery was no good. I couldn't prove it was fake, though.