Originally posted by Genaro92U2:[..]
A little bit of like each DVDChicago, 3D, Boston come to mind
Audio AND video from different nights spliced into the same concert. I don't think it's very common for them to use ONLY audio from a different night and sync it to their lips...they generally just use the other night altogether. Hence why Edge changes positions a few times in UTEOTW on the Slane DVD, and Bono's birthday signs disappear and reappear throughout Chicago.