"Please do not move any equipment. Should you later wish to alter the routing or location of any existing equipment such as cables or wall sockets, you should contact us."
But "please" is a request, so probably not very enforceable.
Moving on, Section G says:
You are responsible for the way the equipment and services are used. You must not do any of the following acts or allow anyone else to do the following acts in relation to the equipment and/or services:
.....edited out the non relevant....
10. use the services in a way that:
i) risks degradation of services to other customers;
ii) puts our network at risk;
Seems to me she's clearly in breach of those (if you're right and it was her bringing down the network). Interestingly, as I read these elements, she'd not be in breach of the T&Cs if she had procured a suitable quality cable and it wasn't causing problems.
Re: Virgin changing cable length terms and conditions
My daugher got a nasty Amazon coax to move the V6 box in her room. It worked ok but soon all the neighbours started having problems with their connections. VM Techies investigating their problem, knocked on my door to ask if they could look at my set up. In 2 minutes flat they spotted it, replaced the cable/fittings with a new VM one, went out to diddle about in the street cab. Five minutes later all was well with the world. I think their cup of tea and a biscuit and their relief that they had sorted a "noise" issue so quickly, meant they didnt take it any further or charge me 🙂
-------------------- John --------------------
My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired 2 WiFi,) SH2 in modem mode with Airport Extreme Router. On VIVID200, Talk Anytime Phone, x2 Mobile SIM only iPhones.