I'm just skimming, but fully 90% of that list could have been left in the British original text for Americans to read with no impediment to comprehension. I mean, really:

Meanwhile, in the changing rooms,

Meanwhile, in the locker room,

And

Quaffle taken by Slytherin

changed to:

Quaffle taken by the Slytherins

both strike me as being a pointless waste of effort.

This might be my favorite

platters of fat chipolatas

changed to

platters of chipolatas

I think if you are a Br-Am English translator (and I did know someone who did that), you do everything. I know that, as an editor, I make certain changes just because otherwise readers might think we made a mistake.

I read all the Harry Potter books in the British English, except for the last one because I couldn't wait for it. I can hear all the British voices of the characters in my head better that way, but I am also fairly familiar with the vocabulary differences.

I don't mind at all reading a story set in Britain or about British characters that uses British English. It gives it flavor and an air of authenticity, and if something puzzles me too much to guess from context I can always look it up.

However, when I'm reading fanfic and Sam Winchester pulls a face because he thinks Dean said something daft or Teal'c visits Sam Carter in hospital to bring her a tin of crisps, I want to hold the author down and force her to listen to Bert in Mary Poppins.

I don't remember tins of crisps from living in England. They came in bags. That must be a very affected writer. Or they're thinking of Pringles.

Obviously I'm biased--I don't mind if the POV isn't Sam's and he thinks Dean did something daft. Just make sure he doesn't say it.

(although I had to hunt down a British person to figure out what the hell a "modcon" was)

What is a "modcon". But I am with Kathy- I read so many old books with references that I totally didn't get that I can roll with it. Although I did picture the Pevensie children carrying electric light up fake wood torches rather than flashlights because they kept talking about "electric torches"

What is a "modcon".

Oooh, note the British punctuation!

From the Jam album All Mod Cons I know it refers to modern conveniences. So in a rental add you would note the flat available had "all mod cons" - like a dishwasher etc.

Which just took me to an Anathem place. I did so much flipping back and forth between the text and glossary that it impeded my enjoyment of the book.

I never once looked at the glossary for Anathem. But I dig on figuring things out by context, and it's helped when being immersed in other languages.

I'm pretty good with Brit-speak, but "pudding" meaning dessert, not a specific, soft, dessert confused me for a long time. As did "Fancy dress" being a costume party, instead of, I don't know, "Sunday, go-to-meeting"(I'm glad I didn't learn that at some Brit's party, though.) Blame Daniel Webster(the historical one, not that fucknut in Florida...aw, blame him too, I'm feeling generous.)

erika! I was thinking about you last night, when I saw Rahm's campaign ad.

I thought it didn't have enough four-letter words in it.