Venues like these have rules about taking photos and I was denied entry with a camera from one, so always ask the promoter about their policy prior to the show. It's wise to offer some photos to the promoter as well as to touch base with them at the event to acknowledge you are the person who called/emailed them previously about taking photos. Being respectful and offering to share the bounty will open doors for you and you'll make a few friends in the process. The next thing is get your seats early and pay for the front row seats if you can. The 23mm X100 lens is wide and you don't want audience heads in your shots, nor do you want to be standing up and blocking the views of others. I typically don't bring my camera if I don't have front row seats.
Ideally you don't want to be noticed and the X100 size and ability to shoot silently is in your favor. My X100 is less conspicuous than most cell phone users because I'm not holding it out in front of me and I have the LED turned off. So in my case unless you're looking through the EVF someone in the audience wouldn't know it's powered on.