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?