One doesn't need to simply mess with the master socket to cause mayhem, and possible serious injury to unassuming OR engineers.
More than a few times over the decades, we've had instances whereby the EU has run a mains cable under a carpet and got it, and the telephone
extension cable caught on the carpet gripper ....... subsequently chucking 240v along our network back to the MDF.
We used to also frequently get the 'Ghost 999' calls, although haven't seen or heard of one for quite a while now ?? This is where the extension wiring in the house has an 'Earth contact' (Insulation rubbed away, again, usually under the carpet where it's walked on), and it would 'Tap' the emergency services 911 (never 999 ??).
One of the older BT guys on here would probably be able to give a reason why it would 'Tap' this number out ..... Loop/Dis dialling or something similar ?? Not my forte I'm afraid.
So, although you are absolutely correct about the licit stance with master sockets, one can do as much damage without even touching said item.