@Bubble92 I think the "not close enough to matter" is exactly it.
You expect (especially with more common names) to see it around and for duplicates in classes, but generally you'd expect someone very close eg your sibling not to give their child the same name as your child for example.
It IS weird to use the same name when it's someone very close who they will see very regularly.
Thinking of names for future children, there's a girls name I've always loved but some friends (who I had never mentioned the name to) used it for their baby last year.
I say friends but nowadays we see each other less and less and are more like distant friends I suppose.
Whether or not I could get away with the name feels like a grey line at the moment.
I think if I did, they wouldn't be annoyed but it does sort of give off a message that I don't feel close enough to them to actively not use it. Even if not consciously, I think it would almost add to the distance as I'm indicating that I'm putting them in the "distant" category.
I'm sure lots of people will insist that it's fine to use a name in any situation but I think generally if someone named their child "Tarquin Winston" and then their brother used the same name the year after, most family members would think it very very odd.
So there is a line. Where that line is does change depending on how common the name is and how close you are but there is a line somewhere.