In case it wasn't obvious, there are social contracts between folks that are established outside of the written contract. Things like, "you should try to give 2 weeks notice when possible" and "you should not hire and change your mind in a matter of months, before the person has worked for you, but after they had already turned down other hard-won options."

Folks who violate social contract are called assholes. You don't go to jail for being an asshole but some folks won't want to work with you and that's okay.