Do tell me what happens when a BU blocked (not just signaling) is mined with e.g. 1.5 MB block size.
if consensus is not reached.. its orphaned. end of.. in the trash in 3 seconds. no drama no fuss
You have misunderstood the question. I was implying what happens once they have e.g. majority hashrate, which they think
alone is sufficient enough to define Bitcoin.
He is mistaken, but for different reasons. BU is a unilateral split. If, after BU pulls the trigger on their hard fork, the Core chain ever overtakes the BU chain, all BU coins will be permanently destroyed and all transactions involving them will be forever invalid. Mass panic will ensue and their altcoin will be worthless. That's why Core devs are begging BU to make their fork bilateral, but they won't listen (or they pretend not to listen because they don't have the competence to implement a bilateral fork).
Oh, that's for the explanation. I just haven't thought about it that much to come to such a realization.
if BU pulls the trigger.. it would do it with majority NODE (over50%) and majority hash(over 50%)
it wont trigger without consensus.
You are seriously confused about this aspect. There is no "majority hash rate consensus" between INCOMPATIBLE CHAINS. The only thing you do with your 51% hash rate is to produce INVALID BLOCKS wrt the original protocol. So this PoW doesn't matter, the blocks are invalid. If you produce 1.5 MB blocks with a PoW that is more than 10 times all the PoW that ever went into bitcoin, then these blocks doesn't count because they are simply INVALID. The old protocol simply rejects them (in the same way as if they were containing wrong signatures in the transactions). The only valid blocks (wrt the old protocol) are those, mined with the 49% hash rate of the miners sticking to the old protocol.
He is most certainly confused and has a flawed understanding of Bitcoin. I can't seem to recall something in my thought process so I thought I'd ask. We know that blocks bigger than 1 MB from chain B would surely get orphaned on chain A. However, what about blocks from chain A being relayed to chain B (considering this would be a 'unilateral split')? I don't see why 1 MB blocks from chain A would get orphaned on chain B under current conditions. Care to elaborate?
Update: I completely forgot about hashPrev. I need some sleep.