I doubt they think that far ahead. Disrupting the grid isn't that difficult. But it is a stupid thing to do. Anyone caught should be charged with murder/attempted murder. Some people depend on electricity for their livelihood if not their in home medical supplies for their life. It's that serious but the way our country is shaping up, it wouldn't surprise me one bit if the entire grid went down one day. That would be a disaster for which we are not prepared.
Just use an EMP and get it done in one stroke.