They will be the majority though, enough to choose the history of the ledger, it's more that they won't allow other validators to join the network, who could invalidate their choices. Thus, the penalties will not be applied.
This guy explains it in detail: https://www.youtube.com/watch?v=gyP0uxxB6V8
How does ETH do to stop miners from rejecting or preferring transactions for blocks today? Pretty sure there have been some interesting stories about transaction front running and other tactics to abuse the system for personal gain (which is a fundamental issue in the unregulated blockchain ecosystem)
