“Comrade.”
Or, “hello”.
A loud two-fingers-in-mouth whistle or that loud tongue clicking noise carriage drivers use to signal “go” to horses is always good to get a reaction from somebody. For baristas it works especially well if you like spit in your coffee.
I asked a non-binary friend about this yesterday. They said there isn’t currently anything, and suggested “excuse me”.
Which has always worked adequately in coffee shops, in my experience.
It’s true that a customer is unlikely to address another customer as “Sir”.
However a member of staff will address a customer that way.
Therefore if I just call out “Sir!” or “Excuse me, sir!” there is a good chance that other patrons will turn around thinking perhaps a member of staff is trying to get their attention.
I don’t think gendered pronouns, or these formal pronouns, particularly help with clearing up ambiguity.
However, you have made me realize that waiter to customer addressing is more likely to require a “Sir” or “Madam”. So there’s still something of a problem in polite speech, but I would still think if someone looks very androgynous, or even more like the opposite gender, they would be used to people sometimes guessing wrong. As long as the waiter is fine with being corrected (which of course they should be; the whole point of using Sir or Madam is to be extra polite), it’s not a big issue.
There are plenty of women bothered by “Madam” or “Ma’am,” that kind of formal addressing has issues even outside of unusual gender identity. It’s not uncommon to hear a woman say something like “how dare you call me Ma’am? how old do you think I am” in response to that.
Sounds like what we *really *need is gender neutral explicitly polite words for “customer” and for “customer service worker”.
So a customer can say “Hello <worker word>!” and the right group of people look up and understand that they’re being politely paged. And meanwhile employees can say “<Customer word>; yes?” and the right group of people understand that they’re being politely acknowledged.
Then we just need words for the other million possible 3rd party interactions out there. 
Or as posted up-thread, perhaps we all should just settle on Comrade!
Excellent user name/post combo!
Really? Because this has literally never happened to me. I’ve never had someone take exception to “Excuse me, ma’am”, or “Thank you, ma’am”, or “Yes, ma’am.” Are you sure this isn’t something that you think some women might take exception to?
Right, because there’s not really an obvious alternative.
If it hypothetically happened, I suspect it would play out like this:
“Madam? Madam? May I take your menu?”
“How dare you call me Madam!”
“I’m terribly sorry if I caused offense. Would you prefer Miss or Mrs or … <pause to allow customer to choose one of these two or give a third option>?”
As I say, I don’t think it’s a big deal, as the whole point of using “Madam” is to be extra-polite. If, for whatever reason, someone doesn’t like that term, then you go with whatever they say. Baroness? Sure. Mr? No problem.
Here are some threads from this very message board on the subject that I found with a google search. But I guess I could be imagining them.
Point taken, though I’m not sure that those threads are referring to the same thing. There’s a difference between “Madam” in a service context and using it in everyday situations.
In most everyday situations, “Sir” sounds strange too.
In particular, as a northerner, I’d find it very odd to be addressed as “ma’am” by someone who knew my name. But completely ordinary if I dropped something on the train and a stranger hailed me as “ma’am”.
If the barista hasn’t started to wait on me yet, I’m going to wait patiently. If they’re really incompetent, I might try to grab their attention, but if a single “Excuse me, could I order a coffee?” doesn’t work, I’m going to somewhere else, don’t have time for that nonsense.
If they’ve already started to wait on me and they’ve turned around to start my drink, “Excuse me, could I get frappuberry sucralose syrup in that?” or whatever abomination I’m asking for should work just fine.
Yeah, “they” is the safest, just use they. I usually use they unless someone has told me their pronouns or I know they’re cis for a fact. Very few binary transpeople will get mad at a “they”. As for the Xe/hir etc pronouns, you very rarely encounter those people, (I think I’ve encountered one in real life) and even fewer who will expect you to magically know that’s their pronoun. I find introducing a new pronoun when we have a perfectly good one… silly, and I don’t think those pronouns will survive in the long-term, but it’s natural that some people will be exploring their gender identity in such ways when the queer movement is moving so quickly. I wouldn’t worry about it, and if someone does get super offended because you didn’t magically guess Xe… well… fuck 'em, they’re a jerk.
I have to admit I have this trollish urge to say “what!? Ma’am!? Do I LOOK like I’m 60 to you?” to a “ma’am” and a “what!? Miss!? Do you think I’m a child!?” whenever I get “miss”. I don’t because it would be jerkish, but the idea of getting offended at both is funny to me. Maybe I should just count my blessings that I’m never misgendered because I took to estro magically, but I also just have such an urge to be a bitch about it. 
It’s not the end of the world to assume a stranger’s gender based on their appearance if you have no other information to go on. The overwhelming majority of people are within the male-female binary and gender non-conforming people are aware of this so I highly doubt they waste time and energy being mortally offended over honest mistakes. Ironically, it’s the cisgender allies who get all bent out of shape on their behalf.
Of course if it turns out your assumption about an individual’s gender was incorrect and you persist in misgendering them, then you are without question an asshole.
+1
The best way I can express it is - if, 99% of the time, someone who looks like a man is a man and someone who looks like a woman is a woman, then it would be very inefficient, and exhausting, to treat it as if it’s a 50%-50% proposition, where there’s only a 50% chance that someone who looks male/female is male/female, respectively.
Absolutely.
I was dubious about some of these examples where one would supposedly need to address a service person using a gendered pronoun. But I agree (and also mentioned) that if someone looks somewhat ambiguous then they are unlikely to make a big deal of you guessing wrong, as long as you’re fine with being corrected and move on.
Or is it the “Political Correctness gone MAD” crowd? You also can’t call brownies brownies any more, dontchano?
I mean, it’s pretty easy to just use “they”. Like, I’m not gonna get in a tizzy about just assuming based on looks, even transpeople do it. However, being misgendered is exhausting, even if you understand why you’re being misgendered and can’t begrudge the person doing it. On top of that, nonbinary people have it even worse than binary transpeople in the respect that almost nobody will ever use their pronouns without explicitly being asked. No, they aren’t likely to be offended, but if you want to make the smallest bit of effort to make transpeoples’ days a bit brighter, or at least easier, defaulting to they/them pronouns is the easiest way to accomodate almost everyone.