You could create a hidden partition in your TrueCrypt volume, put some plausible data in the public partition and give them the password for that.
We live in a very sad state of affairs that will continue to deteriorate.
Um, you realize that you can't carry locked boxes through customs and then refuse to open them, right? That comparison actually hurts the case for taking encrypted data through customs.
But sadly we live in a world where carrying encrypted data is a flag, and will get you more scrutiny, and get your name put on lists.
It also doesn't help if you carry the passphrase on you with your encrypted data.