IANAL as well, and obviously depends on the jurisdiction, but as far as I understand previous discussions: using a tamperproof or encrypted disk is mostly fine. Actively triggering anything that destroys data after you've been become aware of the fact that law enforcement has a warrant is not.

Dead-man switch kind of things are harder to categorize, e.g. having a daemon format the disk if GPS reports locations outside a certain area, or if you don't press a key kombination every 2 minutes (is one allowed to lie about them if asked?)

if you just use encryption you might be forced to turn over the keys.