Pipelines run hundreds, sometimes thousands of miles. It's impossible to guard every inch of a pipeline. Also, if they know what they are doing, they will have it repaired and up and running in no time. I worked on a few exploded pipelines years ago, and it gets done in a hurry. Simple as removing all damaged pipe, which is pretty easy to identify, then replace it with new pipe. It'll be back up in 2-3 days.