…I wonder…
…if its a segregation issue?
As in – there are probably plenty of "xc" riders who turn up, ride round the woods a couple of times, then have a quick blast down the duel or whatever. Now to ride that, under the terms of the lease they need to have paid for their day ticket. As the bike park isn't fenced off from the rest of the wood, they've probably been told that the only way they can be fully covered is to make everybody pay to ride. That way there's no issues with people riding the bike park for free and (shock horror) uninsured.
As others have said – its free to do what the hell you like during the week!
chunky lads on a DH bike
Darren ain't exactly chunky… 😉 And given the poor sod is still waiting to find out whether he's going to lose his foot or not, frankly in his situation I'd be a damn sight less upbeat!