Discussion: How often does this happen?

Regularly!

Only once I can recall here... we had an MTBO course at Dryandra some years back where the roughly 30km distance was actually 40 something. I only noticed when I realised at the 80min mark that there was an awful lot of course to go! Quite impressive to have the entire field bonk prior to the end.

We've had it done at least twice at MetrO events too Tooms (Mosman Park once and somewhere I can't remember)
Surely for something like a bush event it would become obvious through the setting/controlling process?

Ah yes, well, the controller ended up with a broken ankle and never set foot on the map; the course planner was confident that he had georeferenced everything so all the controls were in the right place (I'm still a bit sceptical of checking control sites by GPS) but he had entered 1: 10 000 into the GPS, because that's what it said on the map file...will say I'm surprised that nobody looked at a printed copy of the map and caught on (also why I don't think that setting with OCAD should be a complete substitute for drawing courses by hand in the initial planning stages).