The miners are holding the original chain. They have a massive incentive to do so, as the forked chain Vitalik creating puts them completely out of business. V

The miners are holding the original chain. They have a massive incentive to do so, as the forked chain Vitalik creating puts them completely out of business. Vitalik et al are trying to force a fork, as they did when they left the original ETC chain. Coinbase made the ETC forked coins available, not instantly but once they had time to do the coding to get it set up. Grayscale, who knows, you don't own any cryptocurrency with Grayscale. My guess is they'd go ahead and pull in those additional coins into the value of the fund, but you really have no guarantee of how they would do it unless they've put it in their terms somewhere. All of the coins can be forked. Not your keys, not your coins as the mantra goes.