Along with all the really clear kickstarter disclaimers about how plans change and some things may or may not turn out to be possible. You need to read the whole thing to understand.
I understand that Frontier can't hide behind the terms and conditions of the KickStarter website when their reputation is at stake.
I presume the reason that Frontier have never KickStarted any of their other projects is that backers will not be so easily fooled a second time.