There are literally thousands of nodes in the immediate area. Nearly everyone at the concert has some kind of commlink, and as civilians, few if any are attempting to operate in hidden mode. There's also a lot of advertising in the AR around here, which is unusual for the Barrens. Probably some viral marketing thing aimed at Nabo's primary demographic. Scanning through the ones you can find, you don't see any that pop out as obvious candidates for Nabo's link. Could be he's indoors, and thus out of signal range (wireless blocking paint is cheap, and a common measure to prevent piracy/bootlegging of concert footage), or the commlink is off.