You can restore using iTunes backups stored on an encrypted hard drive in a secret volume. Plausible deniability even after decryption. TrueCrypt does this.

Be sure that as such powers increase they'll obtain more sophisticated tools to help them catch smart alecks.

There's also the possibility of seizure -- not getting your encrypted hard drive back because you refused to co-operate.

But they won't know whether anyone refused to cooperate or not

Otherwise you get rubber hose cryptanalysis: https://news.ycombinator.com/item?id=13629728

Bruce Shneier's advice: https://www.schneier.com/blog/archives/2009/07/laptop_securi...