The referees and scoring people are all volunteer staff and they are doing the best they possibly can.
I've run about 100 VEX events and have given the same statement at the beginning. "The referee's rule is final. If you have a problem with the referee's ruling, see me as the event organizer. You can tell me anything you want, and I will listen closely. At the end of the discussion I will say to you 'The referee's rule is final'. I may talk to the referee about future calls, but I won't override their ruling."
Trying to put up an instant replay, etc. isn't needed. This isn't the NFL, it's a high school robotics competition. And I'll repeat my mantra, "it's not about the robot."
I will say that I have watched matches from the stands, and it's a far different experience than watching the event from the field. I got invited to watch from the sidelines at a Drexel Event. The lights, the noise, the robots being about 10 feet away is a lot of sensory overload. If you get a chance, wrangle an invite to stand on the sidelines. It will change your opinion on refereeing.
I would never want to be a referee. Well that's not true, I'd love to be a "Head Ref", since that would give me access to call Frank and chat.
-1 on the instant replay.