If Tesla fails to deliver the Model 3, I assume they'd need to refund the down payments for all the pre-orders. Similarly, Kickstarter's rules say if the kickstarter is funded but then fails to deliver, they must refund the money (though I have no idea how well-enforced this actually is).
Meanwhile, if Brave completely fails and the BATs become worthless, I don't think anybody's going to get refunded.
Tesla's deposits can be refunded for any reason up until the car starts being produced. So all of those Model 3 reservations are refundable. And some people who wanted for a long time in the queue for Model S or Model X changed their minds (or got tired of waiting) and got refunds.
Meanwhile, if Brave completely fails and the BATs become worthless, I don't think anybody's going to get refunded.