I've been to Ozzfests where musicians were walking among the crowd during their free time. One of them was even handing out Ozzfest sample CDs. Sent from my SAMSUNG-SGH-I547 using Tapatalk
John Boyega walked around in a Clone Trooper costume at Celebration Anaheim. http://nerdreactor.com/2015/04/20/john-boyega-star-war-celebration-disguise/
The first London Celebration (2007) my partner and I were sitting out in the sun on a bench at the venue and Peter Mayhew came out (with a minder) and had a smoke. My partner got some pics but we didn't bother him otherwise.
The photo op area is really chaotic, but I think it got better during the afternoon. Expect delays and having to ask around a lot. The photo op itself was just go up to the person; say hi, pose and leave. No chance for a smalltalk or anything like that. Denis Lawson crushed my damaged shoulder, but it was worth it. Skickat från min GT-I9515 via Tapatalk