Mine are both pee pad trained and outside trained. They are amazingly intelligent and adaptable in that regard.
But they are however still just dogs with the intelligence of dogs, so it doesn't surprise me that my two see whatever is on the floor as a pee pad...they don't discriminate. And honestly, in its own way, it's pretty smart of them that they can put two and two together in this way and recognize that floor = do not pee. But mat ON floor = pee.
They don't pee on my carpet. But if I have something laying ON the carpet, they will tend to pee on that. And it's obvious from their demeanor that they feel like they're doing the right thing!
I"m guessing your carpet will be safe. But whatever you put down ON the new carpet for folks to wipe their feet on, or the pair of jeans that you threw towards the hamper but ended up on the floor, or that magazine you were reading that's laying on the floor.....all fair game!