Great event that I was underprepared for and I surprised myself that I managed 6 laps.
While we are talking about passing (I was passee more than passer) .... Mostly there were no problems but once when I was behind a slower rider I could hear a small group come up behind me. I listened for half a minute but there was just heavy breathing, so I started chatting to the rider in front. Well, on a right turn I hear crunching behind and to the right of me. I turn and look to see some f-wit attempting a pass over piles of dry branches that were sitting in a hole. I said "geez you're keen mate!" and keep riding. He backs off and starts complaining "I've been trying to get past you for ages". I just say "just call track mate, and I'll find somewhere to let you through". He starts up "I HAVE BEEN CALLING TRACK!!" and I hear one other voice in his group "I haven't heard you call track!" Moral to the story - if you can pass me and it will not interfere with me, go for it but if you are wrong about how much space there is, that's your risk: I may or may not move over. If you can't pass me safely, call track: I move over as soon as I can.
The other passing thing that got dangerous was muliple passers. I saw on course a few times that the additional, unexpexcted passer would force the slower rider off track, to come to a complete stop, or in a couple of cases, put them into a tree. When I would call go left / go right I would also say "1 rider only" or "2 riders only" depending on how much space there was and if going uphill, on a turn etc that could potentially hinder / help the passer. Quite a few times I would say "go left 1 rider only" and get back "no, 2 riders". That would be when I would yell "I SAID ONE RIDER!!!" That was respected every time except one time when I put some fast man into a pile of dead branches. It was him or me.