Earlier quoted context omitted.
If you want to play the legal game, the contract is void because it was signed under duress. Forcing the employee to sign in 24h qualifies as consent under duress, not free consent.
First, I don't care whether it's illegal; lying to people is wrong. Second, the definitions for fraud vary from jurisdiction to jurisdiction, but the course of action recommended here falls under the common definition of civil fraud: >"Somebody misrepresents a material fact in order to obtain action or forbearance by another person; >"The other person relies upon the misrepresentation; and >"The other person suffers…
Obviously there would be extra context in practice, whether the candidate has a job, has already resigned, etc... The typical HN commenter in SF already working at FAANG might not be an ideal scenario ^^
Anyway, there's no fraud or misrepresentation, as long as the candidate intended to join the company at the time of signing. If anything, the candidate moving to another company is evidence that they were really looking to move, thus there was no misrepresentation on his intention to leave.