"Counterfeit PlayStation 3 Wireless Controllers, which are practically identical in appearance to genuine PlayStation 3 Wireless Controllers, have been discovered in the market. SCEA advises consumers to be cautious when buying PlayStation 3 Wireless Controllers from uncertain sources as the quality, reliability and safety of counterfeit products is uncertain, and in some cases, may be dangerous. It is possible that some counterfeit product may ignite or explode, resulting in injury or damage to the user, your PlayStation 3 computer entertainment system, or other property. Moreover, SCEA does not support continued functionality of counterfeit or unlicensed controllers in system software updates and these devices may cease to function in the future because of system software updates."
There you go, then. Don't buy dodgy PS3 controllers from white vans in the Walmart car park, don't let your children play with controllers they find in the woods and inform the authorities if a stranger approaches you clutching a DualShock. For once in video games, "It'll blow you away" probably isn't a desirable press quote for the box.
Those who suspect them may already have a ticking time bomb in their living room should probably contact SCEA customer service.
Terrorists! I bought a knock off watch a decade ago and its still ticking and looking good! I'm not afraid to buy a knock off and save a few bucks =P