It's sad that so many comments concentrate on whether luggage is secure in the first place. Of course it is not. The real issue is that having a backdoor makes

It's sad that so many comments concentrate on whether luggage is secure in the first place. Of course it is not. The real issue is that having a backdoor makes a new class of attacks possible. A wilful or accidental leak, for example. Or you can reverse engineer the master key if you have enough locks. The big impact is that one leak kills the security of all locks (of that type). I don't think this would necessarily be the case when looking at (publicly) backdoored encryption. Here, you could have an individual backdoor key for each "lock". Of course, the mass storage of backdoor keys make a mass-leak also more probable.