Cutting a remote power line can have some pretty serious effects. It's not like a well-developed area where the grid can compensate.

You can cut off power to a hospital or nursing station, to freezers containing people's food for the next six months, to water and waste treatment plants. Not to mention power to industrial installations that can lead to spills or millions of dollars in damage.

So to answer the question, I wouldn't do it except in the most absolutely extreme situation. And I try my best to avoid being in situations like that.