If BTU reaches 51%...will they hardfork ? Can anyone see this happening by june 1 ?
I don't think BU is crazy enough to fork without the economic majority. That said, a few pool operators control a large percentage of the hash rate and who knows what long term game they are playing (because they are certainly harming their own wallets lately).
Once it becomes clear that BTU is going to happen (ie RV and others are forceful enough and larger miners are on board, heading for 51%), then the economic overwhelming majority would have no reason not to go with it.
The main objection is the potential disruption (and the principle of stability and Brand). If BTU becomes inevitable, the least disruptive way would be for the fork to carry 100% consenus.
As with ETH/ETC, an insistent core group would probably declare their determination to continue the BTC chain, but the main development would switch to BTU.
That scenario would lead to a price split where the vast majority of hashpower and value was with BTU.
As in politics, there needs to be a lot of discussion to reach maximum consensus before a decision is taken. After the fork, differences need to be put aside to avoid community schism.