I've always wondered about that theory.

Is the point to move liquid shipments to trucks/ships because it's safer somehow? or simply to make it so difficult to transport liquid fuels that people quit using them?

I suspect that pipeline activism mostly results in the former.

Constrained supply or higher cost of transportation = higher prices = incentive to consume less.

I'd prefer to see this dynamic produced by carbon taxes so the price difference isn't going back to the fossil fuel companies, but I'll take what I can get.

Also installation of new fossil fuel infrastructure like pipelines implies a long term commitment to the status quo or even increased production which I find unacceptable.

If the neccessary changes were underway there would be zero demand for new pipelines.

Assuming the pipeline shutdown doesn't result in even more dangerous transportation alternatives being used instead.

underrated comment. especially this company which was in the news for a major spill not so long ago.