New Travel Requirements with Spare Batteries

"Effective January 1, 2008, the following rules apply to the spare lithium batteries you carry with you in case the battery in a device runs low:
• Spare batteries are the batteries you carry separately from the devices they power. When batteries are installed in a device, they are not considered spare batteries.
• You may not pack a spare lithium battery in your checked baggage
• You may bring spare lithium batteries with you in carry-on baggage – see our spare battery tips and how-to sections to find out how to pack spare batteries safely!
• Even though we recommend carrying your devices with you in carry-on baggage as well, if you must bring one in checked baggage, you may check it with the batteries installed."

There's some new restrictions coming into effect when it comes to travelling with spare batteries starting on January 1st.   If any of you like to carry a second phone or laptop battery, you will want to read over these changes and make sure that you are within the allowed amount.  Overall, I don't think this is going to effect me, since I tend to carry my spare phone batteries with me onto the plane.  What I'm really interested to know, is if that USB port on the back of the seat infront of me can be used to charge my devices?  Does anyone know the answer or has been brave enough to plug in their device and find out what happens?