I understand if you travelling in or to the US, you can lock your luggage using the TSA Luggage Lock. (Immigration is still able to open your luggage using their own special keys.)
How about Europe? Especially Heathrow + Charles de Gaulle?
If the TSA Lock is not acceptable in Europe, are there any other alternative precautions I could use instead?
(FYI, information about the TSA Lugguage Locks)
The only possible difference is that in the EU, they may not have the TSA keys. Therefore it just becomes like a normal lock that you have the keys for and they don't. So worst case, they may flag the bag for inspection and require you to open it for them.
Indeed in Europe you're still allowed to lock it with whatever lock you want, so it's perfectly acceptable to attach that, a standard padlock, a combination lock, or any other kind of lock.
If they want to inspect it and can't locate you (in the queue or by paging you) they will simply cut the lock off. Unfortunate, but not the end of the world, and you certainly won't get into trouble.
In my experience, airports in the EU are a bit less strict with locks. I have seen several items of baggage that have normal little padlocks on them, not these fancy "approved" locks.
Wikipedia reports that the system is currently in use in Germany, the Netherlands and in the UK. So your TSA-locked luggage can possibly be opened with the master key/code at Heathrow.
But like Mark and Rory explained, I am not aware of any requirement to leave your luggage open (or to use a special system to make sure it can be opened for inspection) so a TSA lock would still be acceptable elsewhere, just like any other lock.
I was recently traveling from Florence Italy connecting in Charles De Gaulle to US destination. I had a TSA lock on my checked bag and when I picked up my bag at my destination the TSA lock was missing and the eye-ring on the zipper where the lock fits was completely ripped open-so it can never be locked again. I later found the bent unusable TSA lock in my suitcase with my clothes.
