Here's my pitch for why I think a bullshit term makes more sense for this contest then a real term:
Its a WF SEO contest; if we use a term that is already out there, it dilutes the effect of the actual SEO skillz that members can put to use. Someone like me doesn't have to know anything about how to rank for the term "blue widget", I'll just go out and make an offer to whomever owns a site that already is Top 10 for it, that doesnt demonstrate any SEO skill at all, just the ability to negotiate a domain buy. A bullshit term levels the playing field and puts everybody at the same starting point. Also, there are no "non-competitors" in the mix/SERPS
With a bullshit term, the contest can be shorter, everyone that actually ends up ranking in the SERPs for it is going to be doing so because they are participating in the contest, not because they have owned a somewhat-related domain for years and have a headstart that new contest participants can't match, Age and aged backlinks.
Also, with a bullshit term, we have less geniuses yapping about "no way I'd rank a site for XYZ term for these weak prizes, that is worth $94.38 CPC according to [obscure keyword tool], durr". If you win, its a pure win, you demonstrated that you could beat your WF brothers in a fair fight, winner take all. This is a contest between WFers for some cool prizes and bragging rights, not your actual day job.
There is a reason that all the big SEO contests (Nigritude, elursrebmem n7v, etc) used bullshit terms instead of real one, its the only way to truly compare who is the best when dealing with a limited timeframe and tracking actual results.