The last line is what it should be. Now I may be naively swallowing up what the mass media reports, but there were quite a few reports of people getting hurt or so on after leaving a bar, then suing the bar because they (the bar) should have been more responsible and not given them more / that much drink. This is getting a bit off topic now. Since we don't itemise the drinks we buy at the bar (unless someone happened to keep all the receipts for all drinks purchased at the bar), or you reverse engineer security footage, there's not much in a way of the bar being able to defend itself against someone who accuses it of being irresponsible with serving them drinks (in fact, it doesn't even give much help to the accuser even if the bar is actually negligent in its RSA responsibilities).
RSA doesn't also viably cover cases where mates buy drinks for mates, even if some of them are intoxicated for the purposes of RSA. Bar staff might be able to latch on that mates are buying drinks for others and stop that, but that takes much more effort than just evaluating a given patron who is wanting to order something there and then.
Separating the mere action of selling alcohol from the consequences it may result in is almost impossible in practice.
Again RSA a farce here for another reason. Why should they believe you? Just because you said so? Don't intoxicated people do the same thing? Sure, the latter are typically characterised by slurred speech, etc. etc. and other big tell tale signs that you probably weren't exhibiting, but it is still your word and conduct against their judgement. If they err on the side of presuming you are drunk and not serve you anything, they may have lost a customer and you might file a customer service complaint, but they cannot be pinned for any legal wrongdoing (except possibly for discrimination).
I don't know if bouncers have to follow RSA principles. They are told to look out for drunks (or any troublemakers for that matter, whether BAL 0 or 10), but they don't have much to do with whether they'd sell you a drink or not, because they can't / don't.
To round it back out, I fail to see how enforcing RSA to a further extent than it is right now (farcical as it may be) would be an alternative to lock outs in countering violence / alcohol-related incidents.