I recently went on a trip to Germany with some camera gear. The first question was whether or not I should have an ATA Carnet (Definition of a Carnet) or should I just carry my backpack into Germany? Since I have never been to Germany I thought it to be safe and purchase one. For about $60,000 worth of gear the carnet will cost you anywhere from $600 – $800 depending on who you go with. This is just insurance to make sure you are not coming into the country to sell your stuff and not pay the taxes. A few years ago I went to South Africa for a documentary and I purchased my first ATA Carnet. Once home I forgot about it until I got an email from the South African Government telling me I owe them $15,000 in taxes. WTF? After many days of searching around and finally finding the carnet I sent it over to the carnet office and it was rectified, but this does happen.
I also made the mistake of placing 6 of my Anton Bauer Dionic 90 batteries in the checked in baggage in Germany. To my surprise I found a nice little note that 4 of them had been confiscated at the Frankfurt Airport. There is a travel no no when it comes to checking in Li-ion batteries and the limit is 2. You can carry on any number of Li-ion batteries under the 8g of Equivalent Lithium Content or ELC which equates to about 100Wh or less. If you are between 8g-25g ELC then you are allowed 2 loose batteries and one attached to the camera. I just purchased 3 of the IDX Duo-150 batteries which are at 11.5g ELC and will travel carry on nicely.
On another note it is difficult to constantly keep up with how you should travel with camera gear, baggage, batteries etc, so I found this article that compiles most of the information to check on prior to leaving. (Flying Wombat)