Lucky you, Mo!

Yes, I recognise there's a degree of trust involved but then again, you can get mugged on your way home from the pub. And of course, once it's up and running people will have a better idea of who is who.

I've been involved with beginner's and slow sessions before and experienced a similar phenomenon you describe - they all get better as a group and then suddenly there's no room for beginners any more! Hopefully something more fluid will help prevent that.