Australian here. This post reeks of paranoia. Are you moving 10 drives with pirate stickers on them and sweating profusely? If not, don't worry. The border force are only trained to search for biohazards.
A far more likey risk is baggage agents dropping the bag, or leaving it in the rain. But why are you physically moving data anyway? Unlimited gigiabit connections are the norm here, so you could probably redownload whatever it is when you need it, instead of letting readily available copies of pirated media dictate your interactions with law enforcement.
It's completely stupid, especially when carbon itself is untaxed. You're spending $1B to suck something out of a vast and difficult medium that's getting chucked up there willy nilly by anyone who wants to? Why not spend the money putting systems in place to block its initial exhaust? It would be far more cost effective.