Yes, but you also have to know the faster guy is coming, and if he's coming at a speed way faster than you are and you've just mucked up a big jump because you aren't that good...
I am speaking for myself here, but I always try to keep to my line. However, I'm crap, and I often make a mess of a corner, a set of whoops, or a jump because I am trying to go faster than I am safe to go at. If at that moment some guy decides to go by me at a speed 10 or 20 km/hr faster than me, well, he's gonna collect me if he's unlucky.
On an easy track that doesn't happen so much, but on a challenging (read modern) track, much greater chance of it. And if I've just wobbled offline over a double or tabletop cos I came up short, what then? Will the faster guy be able to correct his line while in flight?
Anyways, I know I've derailed this thread into an offtopic theme, so I might close off this Nats thread now it's all done and dusted, unsticky it, and start a new one for Post Nats Debrief?