They do the grid north at rogaines down here, have been known to draw magnetic north on.
The 1:5000 map on Saturday didn't mention it (I noticed quite early it didn't seem to be mag north aligned) but the 1:15,000 map had an offset arrow on the right side of the map. I noticed that early then totally failed to account for it.
I’m sticking with it as an excuse for us to lose 15 mins at number 11, mind you if I had listened to Paula it would have been a different story :(