It's very hard to Police - I don't like the fact we have doormen nowadays, I remember when they were first used on a regular basis, and lots of us didn't like it.
I don't have to, but I choose to have a doorman at 'Lennys', and his instructions are to ask anyone he is suspicious of to name a couple of Northern Soul venues. But if he immediately sees anyone as 'outsiders' - if youngun's, he says it's an over 30's disco, or if older, he says it's a private party - You need doormen that understand our Scene a bit (most are pretty good on this after a brief description)
Northern Soul is for everyone, so as I said, it really is difficult to Police - The main thing is that if a 'situation' occurs, it is dealt with quickly, and professionally.
All the best,
Len