By the early 70s round our way I think the nighters were run until the cops cottoned on to them and they got shut. The membership system was just an attempt to get round the law, I don't think anyone ever challenged the cops, with the drug taking going on it would have been a waste of effort.
The membership system we did down the 100 club in the 80s was a joke by the end, we never got challenged as long as people behaved themselves; and they did-ish.