There is a word for such behavior: Price Gouging.
"Price gouging" is just the free market at work. Movie rentals are far from a necessity, so if you don't want to pay what the market will bear, then don't rent it. Government intervention to prevent "price gouging" is only justified in emergency situations, such as the aftermath of natural disasters, and even then it often does more harm than good. Gasoline shortages after Hurricane Sandy lasted several days longer than necessary because government imposed price controls disincentivized fuel deliveries. Low prices don't help when the storage tank is empty.
I would say that is mostly due to poor planning on the part of officials. When Hurricane Matthew was bearing down on Florida back in October, the state of FL bought up extra gas supplies and kept them at a safe distance but on hand and ready to deliver to troubled areas. Did gas stations run out of gas before / after the storm? Yes, they did. But the state had their trucks out to those gas stations often the very same day. With satellites and what not, a state has days and days to decide whether or not to make such preparations. It is far safer for the community to ensure that people can afford to buy gas to escape the path of the storm rather than let thousands of people die because they couldn't afford gas.