However, if they don't, I think that when using this and winning the game, or retiring, your ruler should by definition come out as "xxxx the Cheat".
So you think Firaxis should add code to check whether any files are named with "multi" (whether saved that way or renamed in the Windows Explorer) and loaded? I mean if I copy the game and rename it, it's using the cheat. Of course since you can rename files in Word, Firaxis should monitor what you open in Word too. And the same for IE. Hey, they could track down any one badmouthing them on these boards that way too.
I'm not serious of course, but realistically, there's no way to check for this particular cheat. The easiest thing to do would be for them to remove it. The better thing (as mentioned) would be to have a save format that disables it. What's very unlikely is them actually checking for its use.