For the bag checking, it's not that simple. I used to know a sound engineer that worked at Leeds festival. I was complaining that we couldn't take in our own booze 'cos they were checking bags. He just pointed out that my rucksack was a camelbak that had the drinks sleeve down the back, use that for booze and hold it for security to have a look. Easy, instead of a 3l bladder it was crammed full of sidekick shots, the main compartment had my jacket, camera, etc, go up to security hold it open for them to have a look through and they never thought to check where the drinks bladder goes (probably not aware of it), saved us a fortune on alcohol. I'm sure the same could be done with flares.
Steve.