Indeed there is, it is called plausible deniability [1]. With Truecrypt, you can nest a hidden volume within another volume, so you can decrypt the latter and it will only show innocuous files, while another password (using other parts of the volume) would provide other (incriminating) files.

I wonder what is in a judge's mind when the encrypted evidence turns out to be kitten pictures and the defendant claims that he does not have any other password to provide.

[1]: https://en.wikipedia.org/wiki/Plausible_deniability#Use_in_c...

edit: clarification