https://github.com/bitcoin/bips/blob/master/bip-0101.mediawiki"Activation is achieved when 750 of 1,000 consecutive blocks in the best chain have a version number with bits 1,2,3 and 14 set (0x20000007 in hex)."
So, what will happen if NO XT miners start setting those bits only to activate prematurely XT? Without the needed hashpower, XT will become surely an altcoin with near-zero value?
The same thing that would happen if a group of miners with majority power decided to play see-saw with the blockchain. That is, they mine ten blocks B(N+1), B(N+2), ... B(N+10) normally on top of some block B(N), then go back and mine 20 blocks C(N+1), C(N+2), ... C(N+20) on top of the same B(N), then mine another 20 blocks B(N+11), B(N+12), ..., B(N+30) on top of B(N+10), then mine C(N+21), C(N+22), ... C(N+40) on top of C(N+20), then...
Every sane person would conclude that bitcoin is a joke, while true bitcoiners will find a way to view that as "good for bitcoin". That is what would happen.