They pick songs as they go along.
/jarmo
Seems the case - they have the lose structure that they stick with, and then change it up as they go along. I know I've heard Axl ask the band 'what do you feel like playing?' at shows. I can't remember if that was at the Nijmegen show I attended or something I heard on a bootleg.
As a sidenote, I bet management shit their pants and reached for the batphone when they saw 'setlist' in this thread title.