When I'm searched, the person searching me often finds my asthma inhaler in my pocket and asks me what it is, which I tell him, but not once have I been asked to take it out and prove it is what I say it is.
The saddest thing about this to me is that the numpties that let off the flares/smoke bombs/bangers etc probably think they are really hard and cool, whereas in actual fact they are just a bunch of stupid little wankers. No doubt the culprits will be bragging about how cool they were at school...