With all due respect to the creator of this brilliant game, I have never agreed with this particular view of his. The thing is that he did not put the prohibition on taking notes in the rules, but considers it something that is disallowed by convention in any game until specifically allowed by the rules of that game. It follows that if you disagree with Mr. Vaccarino about the general convention (i.e., you would not apply it to a game that he had not designed), you equally disagree about its applicability to Dominion, since this is not one of Dominion's rules.
Rules, for all games, say what you are allowed to do within game contexts; they don't say what you aren't allowed to do, because that would be endless. Yes sometimes rules note a particular thing you aren't allowed to do because it's a common question.
I don't believe it's possible to use the prescription, "Do only what the rules explicitly allow" [hence, DOWREA] without at least implicitly referring to unwritten conventions. Tracking the game state is a case in point, as the very strictest application of DOWREA would imply that you can't even track the game state
in your head (or, for that matter, even think about the game at all), since the rules have not explicitly provided for this. This is
reductio ad absurdum, but I think it makes the point that DOWREA is not sufficient guidance on its own to settle questions like this. We reject the proposed restriction
because of its absurdity—that is, its incompatibility with our shared norms—despite that it's not addressed in the written rules. Conversely, it's not addressed in those rules because it's a commonplace, not because it's something you're not allowed to do.
If you don't find the
reductio compelling, consider more physical methods of tracking the game state, such as ticking things off on your fingers or muttering under your breath, or, for that matter, adjusting the position of a play mat, as the OP described in this thread. As far as I know, there is no controversy about doing such things, yet I can't see an objective reason to distinguish them from tracking things on a notepad on the basis of the rulebook. The rulebook says nothing about tracking the state
in any way. If this silence means that, by definition, you are not allowed to track the state, it should mean that by definition, you are not able to track it in any way. I can't see where the distinction between a notepad and a muttered count emerges from the rules without reliance on implicit conventions.