My understanding is that its use is common in the Mozarabic Rite for Feasts of Our Lady, and that this was extended to certain Latin Rite Spanish-derived areas like Mexico. But it certainly isn't in the U.S.
The use of the color Blue diring Advent (and also Lent)is a symbol of dissent.
Yep. I love how these people are all for protecting other people's traditions, but when it comes to the traditional Latin-Rite violet and rose Advent..no, we can't do THAT.
You are correct about the past historical usage of the color - no argument there! But, as you hinted at, blue is not being used as any legitimate throwback to a particular origen.
The phoney excuse of a primitive origen is being used as a cover for dissent.....to confound any legitimate argument of a layman, by dissident clergy. As to the Sarum rite......I know what you refer to, and I dont think it is actually in any regular use.