Post ride report:
Arrived at village with mate at 8:50am and was told shuttles sold out. The website does encourage to book before, so we took the news on the chin, and set ourselves mentally to 'earn' our rides.
First shuttle left ten minutes later with 4 bikes (I'm guessing ~24 capacity). Mate and I exchanged wry smiles, and set off. We rode to the top, down Thunderbolt & Flowtown and back up Packhorse. Took us approx 2 1/2 hours (signage at top could be improved!).
As we ate a (delicious) pie we saw another less than full shuttle leave village (with only 4 spaces empty). We rode Flowtown and back up Packhorse again, and I wasn't unhappy we had to leave to get back to our families, as my legs were feeling it after 1000m of climbing (and 1000m of descending).
As we left at about 1:45pm another shuttle left with just 2 bikes on it.
Now, I can appreciate that if somebody had bought a shuttle ticket and then found they were regularly unable to get on because the shuttle was full they'd be pissed off. So at one level you have to say kudos to Blue Dirt* for knocking back our $100. But… the three shuttles we saw all had spare spots (of course quite possibly some we didn't see were full). And two of them were almost empty.
Surely Blue Dirt could have found a way to accommodate us. Either offered us single rides for say $10–15 when shuttle clearly far from full, or perhaps an informal B-class day ticket where we agreed to be last on each time (and miss out when full).
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* originally this post inadvertently referred to the shuttle provider as Dirt Art, not Blue Dirt. Thanks to dunndog for pointing out my error. Apologies for the confusion.