i think it's important to realize that there is no real standard, regardless of what the scaa's definition may be.
many people will look at the size of the basket and/or amount of coffee used to prepare an espresso and call it from there. 14-16 grams has been considered a double for a long time, and somehow when folks started up-dosing to 20 grams or more, half the people just called those doubles, and others started calling them triples.
how can we possibly define something like that? a double for me is your triple.
folks over at coffeehouse NW pull with 20 grams(ish) and call that an "espresso". For them each portafilter locked and loaded is considered an espresso, regardless of wether they are using a double basket or triple.
at barista, we have on our menu that our espresso (all served as "doubles") will range from a 1 ounce ristretto up to a 2 ounce shot depending on how the coffee pulls.
if anything, this just invites more of a conversation with the consumer on what espresso really is.
btw, something that some shops in pdx are doing now is charging a dollar for an extra shot of espresso. if all drinks are doubles, then that extra shot (single) that we are charging for (often for .50) and putting in our drinks is actually costing us close to that amount. so we're not making any money on it. charge them a dollar and give em a quad.