Well that's not exactly the case. If you've got pick 15 and the guys you had graded out as being worthy of that pick aren't there, but the next guy up is graded as being a 2nd round prospect, trading down is still "sticking to the board".
That being said, my entire point of what I said was that no one "sticks to the board" in the literal sense. That they don't always stick to the letter and law of their draft boards once the draft gets rolling so you can't say, "If they hadn't taken Escobar, they'd have taken Ryan Nassib because he was next on the list." when they already DIDN'T take Floyd where they had him graded at. You can't have it both ways.