Sabotage?I can't imagine any group of radical opponents of environmentalism trying this kind of stunt. All the risk is on the side of those wanting to get at the oil and transport it. People aren't going to even want new pipelines near their towns of they start thinking the things will start blowing up all over the place. (Never mind all the pipelines already in place - out of sight, out of mind.) I just can't see anyone trying that kind of stunt for the purpose of pushing pipelines - too easy to demagogue from the anti-oil people.
If it was sabotage, what interests did the saboteurs have in mind? They could have been opponents of fracking, but they could have been proponents of pipelines — radical environmentalists or radical opponents of environmentalism.