Yes, they have valves that automatically close when there is a sudden pressure drop, and technicians watching guages, monitoring every aspect of the pipline.If something goes wrong, it can be shut down immediately.
The BS about uncaring oil companies spilling oil all over the place through negligence is just that, BS. They are in the pipline business to make money. When that line is shut down nobody makes money.
Stockholders, including most pension funds, are invested to make money. Therefore it is in everyone's best interest to keep it moving.
During the Arctic winter, if it is shut down for an extended time, the oil would become so stiff that it could not be coaxed into moving again until summer. Stockholders would demand heads roll for that. This is only one more incentive for it's managers to keep it in top shape.
It is interesting to note that the only two major leaks were deliberate acts of vandalism. The latest perpetrator is on trial here right now. He faces several felony counts from his actions. The clean-up is still going on, months later.
The construction is indeed a beautiful thing, especially when one considers the remoteness and adverse weather conditions encountered by the workers. Kinda disproves the theory about the inferior American worker, doesn't it?
As far as ANWR being a beautiful place, that's a matter of opinion. It's about half surface water, with the other half being slightly less wet. In the winter it is a barren wasteland, occupied only by small rodents and Arctic foxes. Even the Caribou get the H#$%l out of there and head for greener pastures. Polar bears hibernate.
In summer, besides being mostly water, mosquitoes are so thick you literally inhale them with every breath. A warm day can reach the low 80's, but the average day will top out in the 50's or low 60's, with a constant dirzzling rain. All in all, a really good place for an oil field, caribou, and not much else.
BTW, on hot days I have seen caribou resting under the modules to escape the worst of the mosquitoes. They are really belligerent when you accidentally startle them.