Yep. Including many well-trained and expensive lawyers.

There are no absolute rules or numbers; there's just "fair use is an amount that encourages progress & allows free speech without stomping too much on the rights of the original creator."

If that sounds vague, it's because it is. And scary for the people who are on the receiving end of Cease & Desist orders, because there's no standards for what is, and is not, reasonable to take to court--it's all about whose lawyers are willing to keep playing.