It should be easy for both members and non-members to contact the community manager. Contact details should be clearly visible. You shouldn’t need to register to find them.
If your contact details aren’t easy to find on the community, you have no idea just how many opportunities you’re missing.
Connected communities are hot at the moment, I predict they’re going to be hot for a very long time. Companies, organizations and important people are increasingly turning to communities for collaboration.
Case in point, Mumsnet charges companies to run competitions to send their members on amazing trips. It’s not hard to find their contact details neither.