Two comments.

First of all, it's possible to have different accents singing and speaking. I remember back in the 1960s I was puzzled because I would listen to the Beatles speak and they had a decidedly English accent, but when they sang, they sounded American – unlike other British groups like Herman's Hermits for instance.

I don't think with the Beatles it was a matter of trying to speak with an American accent. I think the fact is, they spent so much time listening to, and singing American music, in particularly rock 'n roll, that they developed that particular accent while singing. I don't think it required a conscious effort or desire to "fake" an American accent; I think it was a natural development, just as a person develops a secondary accent when they live for a while in a country different from their native land.

I know that I myself, having spent so much time singing Celtic (Scottish and Irish) music, have developed an accent when singing that is different from my speaking accent. I wouldn't call it a Scottish accent, or an Irish accent, but there are some elements of that in there. I'm not trying to "fake" a Scottish or Irish accent, it's just the way I sing now.

The second comment I have is directed to the person who says they particularly hate when someone tries to sing in a "fake" Scottish accent. Bear in mind that it may not be an accent you're hearing. It may be that the person is singing a Scottish folk song that has words of the Scots dialect in it. A lot of Scottish music has Scots words in it, and a lot of the time they just don't sound right – they don't really scan properly – if you don't use the Scots pronunciations for the words, for example hae, hame, lang, dee instead of have, home, long, die. So it may not be accent (fake or otherwise) you're hearing – it may be a legitimate attempt to properly pronounce Scots dialect lyrics, in order to sing the song properly!

Finally, I'll just say that I sing because I love the music. And I sing it the way I want to hear it sung. That's all. I sing the music because I love it, and I sing it the way I love to sing it. And if you don't like it, you don't have to listen.