The 'law' refers to the BT line INTO and as FAR AS the master socket. I suspect you'll find its up to and INCLUDING the master socket,
- not sure whether you are arguing or agreeing
For simplicity, note there is NO wire 3 up to the Master Socket from the Downside line and therefore 'tampering' with it is not against the T&C. There is a lot of information you can find on the web about this.