Insist on HR's OK before revoking job offer.

Train all your supervisors to seek HR's input before acting on any hiring or firing decision.

One best practice: Have HR do the task of transmitting termination (or offer revocation) news, not the supervisor who made the decision. And, for heaven's sake, never communicate bad news via text or social media.

Recent case: A Louisiana restaurant manager hired a server, not realizing she was pregnant. When he found out, he decided to withdraw the job offer without discussing it with HR. Instead of calling the woman, he sent her a message on social media saying, "I'm not gonna be able to hire you. I didn't realize you were expecting a baby..."

She reapplied weeks later...