I went to the NASCAR race today. (Free tickets.) I didn't carry, and I didn't see any signs, but they did have security at the entrances which I expected. They asked me if I had any metal/cell phone/knives in my pocket. I said I do have a phone and a Swiss army knife. (I wanted a knife and a beer opener.) They said ok then I stepped up to the guy with the magic wand. I held up my Swiss army knife, and when he was about to wave the wand, I remembered I had a Gerber pocket knife still in my pocket. I didn't say anything and I let the guy finish with the wand, and then he said "Ok...enjoy the race".
That magic wand wasn't very magical.