Hmmm.
My friend got into KF last year and he was thinking about "gaming" them but before he could, his other schools all sent him letters saying that they know he had been admitted to KF and that is app was now withdrawn.
If you honestly thought is wasn't binding than you get a pass, but if you did what MBA20 is suggesting than its against their policy.
There is a another member on here, forget his name, that has 4 schools EA in his profile!
I think sometimes people can get confused about how these rules work.
UNC/DUKE are both Binding.