They also usually use some weasel words like “up to.” That way, if it doesn’t last the full 72 hours (which it won’t), they can claim that they stated “72 hours MAXIMUM” rather than just “72 hours.” It’s basically shifts the statement from “lasts three days” to “definitely won’t last four days.”

It’s either a typo, or a lot or sass for a PopSci article.

“Look at this huge, unparalleled rise in carbon levels millions of years ago, it’s so huge… Psych! We do that every five years! Buckle in, buckaroo, things are about to get bad!”

You’re fine - I grew up in a rural state, and I thought they were super rare until I lived in a city where the public transit system gave them as change.