I lost my MFLB at a concert doing that about 3 years ago. I was in the crowd in a small venue taking a hit with my fist up to my mouth basically. And this guy taps me on the shoulder and signals "come with me" -- I immediately knew what was up and tried to hand it off to some random person in the crowd. The person didn't know what I was trying to do and then the guy was like, "you come with me too."
I ended up tossing it on the floor behind my back and following the guy. The security guys patted me and random dude #2 all over the place and then mentioned the cops, blah blah blah. I said "I don't know what you're talking about and neither does he! I don't even know that guy!" "Don't make us call the police."
They kicked us out. Lucky for guy #2 he just ran back into the crowd real fast immediately after he was out of sight of the security dudes. My shirt was red and really identifiable though so I was out for good. Think about how much bullshit it would be for that random guy to just get randomly kicked out like that.
I'm glad he made it back in over me.
SOOOOOOOOOO point of the story ------- no matter how stealthy you think you're being, someone who is paying attention to you can certainly notice. "hittin da droogs!" I was at a KYUSS concert of all bands - a pioneer in the desert/stoner metal genre. It was a tad ironic but it was the venue, not them obviously.