The creator could of course power down and run off with the STEEM, and then people lose their guaranteed SBI, and assuming that everyone did not get 100% of the STEEM they invested back, then it could be called scammy. But they haven't done then, and me personally I've made all the STEEM I put in, and then some.
Realizing I should have talked to this part separately. Joseph Savage is on my driver's license. The largest SBI member is @contestkings. @dkid14 is one of their partners, and lives only two hours from me.
The likelihood that I could exit scam without serious financial and/or legal repercussions is zero.
At a minimum, if I close the program entirely, I would be bound by the terms of the refund policy, fulfillment of which would leave the accounts empty of SP.