Hah.
I wouldn't go that far. I lock the door, so to speak, but the windows aren't exactly barred. It's pretty much an open secret at this point that you can copy the save folder fairly freely.
To be blunt, it is an arms race I am destined to lose. You can't really have a 100% anti-cheat game that is run locally anyway, trying is just wasted effort. I do enough to discourage completely casual heat of the moment cheating and leave it at that. I'm not swearing to never go further, but I admit "going further" would be more likely removing leaderboards than anything else: as I said, it's a battle you can't win with a game played entirely on the user's system anyway. In the end, they have all the control.