So interesting discovery - on the whole competing HA priorities thing. I was tracing my phone line some more, two interesting points:
1) Demarc box is actually in my crawlspace just on the inside of the house from where the wire runs. There is what could be the biggest hack for lightning protection - a wire not actually tied up, dangling loose, running over to a cold water pipe. What I thought at first glance was the box is actually just some jury-rigged mechanism for holding wire against wall. It's 12' up, so I didn't clearly see it first time.
2) ADT ran the wiring without an RJ31, it's just a regular extension twist-tied along with the other extensions.
Wife is royally pissed about both my discovery about the ease of cutting our phone lines, plus the RJ31 thing. She wants to call ADT and get 5.5 yrs of fees refunded for providing a false sense of security. No way would that happen, as they could just say that "line seizure" is an optional feature that the prior owners who did the ADT install 10yrs ago didn't pay for, but at least now she's of the ilk that the Elk must be operational ASAP.