For what it's worth, at Elmgrove we already offer a semi-cloakroom service, though it's on a really small scale! If anyone wants to leave car keys, bags, coats etc behind the desk then someone looks after them for the night.
That's a free service - there's usually someone on the door at all times, so there's room for some stuff behind there, but it's a bit limited for space, and we don't have an official ticket system running.
In an ideal world, it would be nice to be able to have an official cloakroom / ticketing system included in the price of the class, but the size of venue doesn't really justify a full-time person doing that unfortunately.
We also have a (slightly cautious) system running for strangers: if anyone wants to just come in and watch, then they are invited to sit at the front desk under supervision. Strangers cannot sit in the hall unattended.
John.