But it should read 2 spare tubes...per racer...for the first bike leg alone.  Because that's how many blowouts I've gotten both times I've ridden it.  The first bike section of the race is gnarly.  To the racers, I'd practice two things:

1.  riding gnarly trails

2.  changing flat tires

Both of which will be critical, as the first bike leg of the course does have a cutoff at the end of it.  At this point, we believe it may be the only cutoff of the course.  That said, it's a very important one to make, so you won't want a bike-leg-turned-bruised-leg or a blowout throwing your race off.

Now, what is a gnarly trail, or more importantly what is a gnarly trail that would cause so many blowouts?  Think rocks.  Hard rocks.  Embedded in the ground in dry Georgia clay (read: they might as well be set in concrete).  With sharp pointy teeth.

Don't believe me?  Just look at the tubes laying about!