Methinks this is actually the FBI trying to violate the 3rd Amendment:
A secondary reason for “quartering soldiers” was/is to overtly keep an eye on subjects precisely to discourage subversive activities.
By forcing security system makers to install back doors, the potentially subversive will hesitate, knowing the FBI can peek at what they write & doc not too different from having a soldier watching their every move.
I actually contemplated including the the Third Amendment in my thesis for those very reasons. Thanks for adding it.