In the past I have had this happen many times, I was required by policy to inform my superior about being approached. I later took the same policy and put it to use.
If you start a physical, business, or romantic relationship with a co worker it must be disclosed to your supervisor by the person being approached. No exceptions upon possible disciplinary action including separation.
All supervisors put this info into a data file and shared it, under the radar, if this person has done this before and if there were any concerns. If there were major problems, she would have been dismissed, but sometimes transfered out of state. Later if there is a problem where the company suffers from it the person who approached another employee for sex, relationship, or investment would be the person fired.
I personally have always notified my boss that I was approached or was going to approach another and have always received great information before shooting myself in the foot. Once that she claimed rape against a co worker...
I now don't have the opportunity since I am THE BOSS and the lawyers told me "no fucking way."
There was this redhead, back before getting married, who told me that she just wanted a roll in the rack, nothing more, my boss told me she was worth losing a job over!!! It ended when I became her boss and yes it sucked knowing she was fucking the next me who was my employee too.