Re: "Cheating" to survive a real fight
The UFC cage fighting example is a good one. In the very earliest days of UFC, you had people fighting specifically with their arts - ie a Muay Thai person against a JuJitsu person etc.
Over time, the differences between professional UFC fighters has diminished so that most of them now fight with very similar styles. They all incorporate good boxing techniques, take downs, grappling, ground'n'pound etc, because that is what works - especially against other highly trained martial artists.
IMO if you put even a high ranked Aiki or Jujitsudoka in a cage fight with these people, and the "traditionalists" stuck to their style, they would be slaughtered. This is not to say that a well trained and experienced Aiki or JJ fighter would not be effective against an average joe, or even an above average joe from the street.