Not really. It's not hard to pull off you just need around 4 people, maybe 2 would work, too.
Getting illegal short term access to the cables around there long runs isn't hard. Like at all.
Finding which cable need to be cut is a bit harder but not too hard either. (It's not a state secret or anything, there are quite a bunch of people which know stuff like that. Worse just by following news in recent years about what interruptions cable theft caused is probably enough to find out where you need to cut cables.) Sure it involves a bit of planing and research etc. But nothing which is beyond what a small handful of misguided but not very stupid people can archive. And in my experience people in the group I mentioned are not stupid at all, misguided sure, but not stupid.
