Yes! Don't get caught for one thing as you'll either have your camera confiscated and/or you and your mates will be shown the door

But we'll take it as you're already aware of the risks, I've gotten into the NEC with a film SLR and a 200mm lens, just think carefully where you conceal it
Forget flash for one thing, usually you are going to be so far away from the stage that the only thing you will be illuminating are the backs of peoples heads, this also leads the camera to underexpose anything outside that area!
I'm tipping this is what happened to your very dark shot above, not to mention flash is also a good marker for the bouncers to come looking for you
Up the ISO on the camera to the highest and the F stop to the lowest/widest setting, this will give you the fastest shutter speed possible, sorry not familiar with your camera, suggest experiment and see.
Oh and enjoy the concert