[yabadabadoes]

It can and should be made illegal which is the only practical countermeasure for most things. (I.e. every electronic device manufacturer is relying on EMP disruption devices being illegal.)

In Switzerland it is usually illegal to cover public space with CCTV and one is required to post signs visible before entering a private space with CCTV. AFAIK this rule technically would and should apply to guests and video in the home. It definitely applies to businesses filming employees.