Club Membership

I recently attended an audition at which the auditionees were advised that, if successfully cast, we would be required to join the theatre club concerned. Absolutely right and proper, no issue with that. What I had a problem with was being told that if we did not join we would be uninsured in case of accident. Now, I know that clubs are required to have Public Liability cover and I very much doubt that the cover is restricted to members only. What happens if a non member audience member has an accident and the club is liable? I believe that anyone who is on the club's premises with or without permission, member or non member is covered by the club's Public Liability cover.Am I right in thinking this and if so, then the pratice of telling auditionees to join for insurance cover should cease, they should join because it is the right thing to do.Coments welcomed, Cheers