Ideally, neither party would offer meaningless pre-interview/discovery numbers and both would be willing to accept nearly any number that made sense after agreeing on the likely quality of the applicant-candidate fit. In practice, neither of those things are true and an early number from a candidate is treated like a late-stage number should be. It's much easier to leave the number out than to try to fix that.

And as an employer, I'm certainly not required to give a number. "Market rate" is sufficient to start a conversation with a serious applicant.