Way too many credible people who actually were there confirmed that there was indeed a fourth row. Remember every iteration of the show leading up to the premiere involved a 10-in-60 rule. And we know from the legacy of CHAIN REACTION that having an unwinnable bonus round at the outset never stopped Bob from selling a show.
Maybe there's a game show here...where the less obvious clues are revealed at first, with the goal to identify what's at the tip of the iceberg? Double Dare with an Anarctic theme? Danny DeVito as the host?