Grey market items from Asia are a bit different though because they aren't usually UL approved. If a non-approved charger burns down your house, it may nullify your insurance so that's not something I would mess with personally. If however you DO get a genuine Canon charger and battery (which can be difficult to tell) and it is UL approved, it is difficult for Canon to say they won't service the item. Notice in the press release that it says "MAY not be eligible", not WILL not be eligible. Warranty service by Canon USA would be billed back to the factory, so it doesn't cost them anything to fix it AND the fact is that if they are genuine Canon products, they come from the same factory with the same name on it. Canon USA is also a wholly owned subsidiary of Canon Inc. who in the end, has to support their products.
If you have a genuine Canon product and you make enough noise, they should honor the warranty regardless of where you bought it.
BUT Beware of non-approved knockoff batteries and chargers. Those will void your warranty and possibly endanger your life. For me, the risk of saving a couple of hundred bucks isn't worth it. If you are talking about lenses and non-electrical accessories, it is less risky. Personally, I'd rather have local support as well as supporting my local dealers. Go negotiate!
None of my Canon lenses has so far required a battery or charger.
So what is the excuse for making them country specific, or not servicing them in different counties - it can only be to deliberately segment the market to optimize profitability.