The dispute would be between the State and the Dapp.
That would be handled in State courts. A ruling or order from the State court would then be forwarded to ECAF under 5.4 External Courts . Then, see @samupaha's response above - firstly ECAF would have to accept and forward the order, then the BPs would have to accept and execute the order, then the Community would have to accept and not referendum / vote out the BPs.
Lots of checks and balances.
RE: Proposal for an incremental Constitution and Dapp layer governance on EOS