I tape (audio) fairly openly at a lot of shows, most venues (or at least those who work for the venues) don't appear to care these days as long as it's not taking up space/getting in the way.

And a lot of artists are also pretty tolerant at this point of it. For example, The guy who runs the excellent (unofficial) live archive for NIN, got an invite to meet the band rather than a cease & desist.

(Edited for wording).