[mb-style] Guest performances again

[Philip Jägenstedt]

I'm a bit confused about guest performance AR:s again. The helper text
on the AR editing page reads "This attribute indicates a 'guest'
performance where the performer is not usually part of the band."

Should this be understood to mean that whenever a performer isn't part
of a band (or isn't the artist him/herself in case of an individual
artist) but has credits for some performance, then it is a guest
performance? If that were the case then we'd have "guest drums
performed by Drummer Guy" on as good as every pop artist release which
doesn't have a regular band. This doesn't seem very reasonable.

So, is "guest" only for when the artist is credited as a guest?

Two very specific questions:

1. Does "featuring" imply guest?

2. In a duet between artist A and artist B released by artist A
without any special credit given on the cover (but probably "vocals"
in liners), is artist B performing "guest lead vocal" or just "lead
vocal"?

Philip