TOPIC: Capo use?

Open 'G' tuning GDGBD correct? O.K. now when a capo is put on 2nd. fret now the strings are a whole step up and now in key of 'A'? If correct when does the 5th. string change? or does it also change even in the capo on 2nd. fret?

Bluegrassbrown

The 5th string also must be capoed to correspond with the capo at the 2nd fret. G will now me in the Key of A. The capo on the 5th string should be at the 7th fret.

Dave
www.fretmentor.com

The capo is your friend.

Does anyone here use a capo when playing solo instrumentals?
I've wondered about this for a while in some youtube videos and
lately in some tab's calling for a capo. Without needing to
match the key of another instrument, or wanting to fit some
particular fingering into someone's vocal range, what's the
purpose?