But here's what I don't understand about this: wouldn't that be the company revoking the offer, not the employee? If the company revokes the offer or has "exploding offers" or whatever, that's a corporate thing, not an employee issue.
2. Company B says "we'd like to hire you at $X/year"
3. Person A says "that sounds good, I'll start in a month." Company B stops trying to fill the job.
4. Up to a month passes.
5. Person A tells company B "lol nevermind" and doesn't actually start work. Normally this is because company C is offering to pay $Y and $Y >> $X.
It's an employee issue because the employee is not following through on what they said they'd do. Because employment is at-will in the US they're legally in the clear, but the company that was planning on hiring them is still kind of screwed.