Shutting it down? are you for real?
To pause the contribution round now and to show they can deliver would help them in avoiding the enormous risk of as someone else here already mentioned of becoming 'the next cuil'.
Hype is a double-edged sword, it's great when you have it but you only get one shot at delivering and in an overhyped situation that is much harder than in one where expectations are still realistic. The more money they pull in the more this will be overhyped, the bigger the chance of a public disappointment when they launch.
Most likely the public interest in this project will die out within 1-3 months. Hopefully they will not ruin their future lives endlessly trying to reproduce this incredibly lucky strike.
But while their at it, they should get as MUCH as they possibly can and totally and shamelessly go for it, hacking, hiring other people to work with them, getting drunk in parties at the other side of the globe, whatever...
Giving that money back saying they are afraid to disappoint some anonymous crowd would be totally nuts.
If they go getting drunk at parties on the other side of the globe there is a chance they'll kill kickstarter as collateral damage besides their own project.
Taking in funding - even if it is 'throw-away' cash - comes with a responsibility, this is not a 'lottery', and the crowd is not anonymous.