Spit in your face bet

Hi, I was wondering whether any of you have heard of the term, spit in your face bet? I ask as i was once told this was a phrase when someone gave me a tip. Saying that its the kind of bet where you go into work the next day and spit in your bosses face. In other words i pressume a almost dead cert tip. I was wondering if any others had also heard this term used as I have only ever heard it once! Cheers.