The "free vacation" is a scam, but the idiot that started this whole "yes" thing is an even bigger scammer.  Here is an idea.  No one should ever say "yes" again, anywhere.  After all, everyone has smartphones that can record, you never know when someone might be recording your "yes" and then run right out and open up bank accounts, credit cards, and other stuff in your name, simply by playing the "yes" recording.