Gang Vocals?

Here lately I've noticed a trend with new releases: gang vocals. The more I think about this, the more I think "gang vocals" is a dumb phrase.

Lynam and Motley Crue both feature gang vocals on their new albums. In both instances, those "gang vocals" are by an already famous group of musicians. I remember when this was credited as "backing vocals." The liner notes usually said something like "backing vocals provided by ...." or "so and so appears courtesy of Universal Records."

I wonder when semantics crept into modern rock and changed the way we think of layered vocal tracks? I mean, is this a ProTools evolution? It's pretty common for rock musicians to think of their respective bands as a "gang" and yet the term "gang vocal" seems derivative to me. 

I wonder how many more Glam bands will use gang vocals as a marketing tactic on upcoming albums?

**What do you prefer: vocals by your favorite band, or backing tracks provided by other famous musicians?