No, they don't have to. They still often do, however. And when they do explicitly include such verbiage, it's easier to get it waived or amended (as I've been a

No, they don't have to. They still often do, however. And when they do explicitly include such verbiage, it's easier to get it waived or amended (as I've been able to do at nearly every position I've ever taken). Counsel is far more likely to modify an existing clause than to add a new one, IME.