What makes you think you are fooling it?
Does not the example make it clear that you actualy have the abilitiy, and actualy use it, but only to activate the item? The item example was made illustrate that.
I agree that if you have a different idea of how UMD should work, then just add salt, and change it.
But the rules seem very clear Lidda did get the TU ability, and could only use it to make holy water.
Nothing in the rules suggest you "pretend" anything.
I suggest the "Can't use" means that unless the item can use (or requires) the emulation to access its powers, you "Can't use" it.