You're damn right it is

Even when the last name is "Bates"?

And when was the last time you heard someone called master in a newspaper or actual life?

> I was always taught it was 'Master' for unmarried and young men.

I remember when I was a kid, bank correspondence would address me as MASTER. I found it amusing.

I don’t think they do that anymore though??? I think our son has always been MR to them, even when he was a 5 year old

I see it used a ton in an airline context.

Commonly abbreviated as Mstr. I believe.

Which country? Never heard of it in the US but feels like a commonwealth or UK thing?

Australia

I knew someone with the surname Bates, that was amusing when things like his bank sent him letters when he was under 18.

I'm in the UK. Letters from healthcare providers regarding my minor son is addressed as "Master <name>".

[delayed]

And when did you last use that instead of Mr?