I'm wondering how they could recognize such sick desires in each other through that site.  Been on that site, and can't imagine one could post something that hints about behavior like this.  Maybe there are some covert phrases that could be used, unrecognizable by the average person.  

Whatever the case, all sites need to police their activities.  Heck, maybe they could use 'Civil'.  LOL.  Those are two sick people.  The lady who acted on this is indeed a "hero".  The two who engaged in this are sick and need to be kept out of our civilian society.