Please remember that this is not an official statement, and is a rumor.
via an anonymous source from the Faeit 212 inbox
I can confirm 100% that escalation is NOT being used at throne of skulls, but stronghold is being used. GW is releasing a statement soon saying that escalation is to be an expansion ("like planet strike") and that Stronghold is an update to the main rule book.
No word yet on whether they will ban the two Aquila Strongpoints (the str D cannon and missile ones) from their tournaments, but like previously said I am 100% that escalation is NOT being used, whereas Stronghold IS.