Yup, your aunt got a dose of coffee snobbishness I'm afraid. The worst I've experienced recently was when several of us went into a specialty coffee shop that I'd been recommended in Saigon. All except for one ordered ordered coffee. My last friend can't handle anything with caffeine so she asked what other drinks were on the menu. There were none, no non-coffee drinks and no decaf either. Eventually we asked what the ~5 year old child on the table beside us was drinking. Babychino (foamed milk). Great, it's not on the menu but she'll have one.
They charged us $6 for the babychino, or more even (180k VND I think). When we complained they pointed out the tiny print on the bottom of the bill that there's a surcharge for anyone who doesn't drink coffee. Imagine if a bar did that.
That's stupid, it might be impressive they know the difference, but what if I actually wanted an Americano? (Hot water added, vs espresso pulled into it in a long black.)
I'm not so snobbish as to care (and I prefer lungo anyway - long shot all brewed, no pure water added) it just seems to me if they're going to be like that then they should recognise they're different and offer both. 'Certainly sir, or if you prefer we can do a long black too' sort of thing, acknowledging that the customer may be just as snobbish/knowledgeable, but accustomed to ordering Americano because 'long black' would generally raise eyebrows.
I do think in hindsight I may have experienced it though, in the UK - I didn't order, but my aunt or someone was told they don't do Americanos and came back with a filter coffee or something. At the time I thought they were just incompetent ('do you do espressos? Hot water?' I would have not been able to resist retorting) but now I think probably it was similar to your experience. Stupid.