Another implication of the parallel axis theorem is that the attacker could perfectly mimic every moment of inertia by shaving plastic. They wouldn't have to know which two axes were being tested because there are only three real numbers worth of information in the system to begin with (once center of mass and total mass have been dealt with.) In the whole MOI tensor there are only six free numbers which sounds like a reasonable number of parameters to fix by adding and removing small amounts of material.

What was this company doing in hiring an untrustworthy manufacturer to handle secure devices? That's playing a game you've lost from the start. Not every problem is technical!