Even if they do know, it's still an awful decision to take. The less likely outcome is that everything will go fine forever after. It will very likely either

Even if they do know, it's still an awful decision to take. The less likely outcome is that everything will go fine forever after. It will very likely either become a mess (awkward situations, loss of job even for third parties, etc.) or a disaster for everyone involved (like a sexual harassment lawsuit.) Espcially if you are the boss. And even more if the person wasn't working there to begin with!