Extra PS4 DualShock 4 controllers don't come with their own USB charging cables
Now, we know this isn't the end of the world, but a quick look at the back of a (Canadian, admittedly) DualShock 4 box confirms that the accessory does not come with its own USB charging cable.
The packaging of the DualShock 4 (pictured above, and sorry about the quality... it had to get from Canada to Australia in my carry-on) states, "A USB cable is not included. To connect or charge the controller, use the USB cable supplied with the PS4 system."
So, out of the box, gamers with more than one DualShock 4 will only have the capability to charge one controller at a time... unless they happen to have extra USB Micro-B cables at home. If not, extra USB cables aren't too expensive to obtain, but after spending $100 AUD on the extra controller, it is an additional cost gamers mightn't have been aware of.
Extra DualShock 3 controllers for the PS3 also shipped without an additional power cable.