Unfortunately I can't change it - I'm just a lowly (albeit interested) user, I don't run the demo sites ;-)
But you're actually right - the "latest" site does explicitly state that users ought to be able to access the dashboard...hmmm.
Again, unfortunately, it seems the demo site has been down for ages, and the latest site is also not getting much love lately. Perhaps someone at Tangent Snowball ought to decide whether they want this project to be properly maintained going forward...
If you're willing to invest a few minutes and you've got a unixy command line, it *is* quite straightforward to get the sandbox site running locally.
Will