Edited to remove a quote of that which was removed to edit for clarity in a previous thread ... JT
There seems to be this perception here and in the media that the 94 took off 2 minutes after the 12 and sat there 1000ft below and 20 miles behind for 2 hours until it hit the wake.
Unlike years gone by, it is very rare to fly on an airway between the US west coast and Australian east coast. You could head down just north of Tahiti today and north of Honolulu tomorrow with a plan full of Lats and Longs and no waypoint names. Most plans are on "User Preferred Routes" that may be similar but not the same for any two aircraft. What it does mean though, is that United, Delta, ANZ, Fiji, Qantas, Virgin and the rest will all depart at similar times, will often be occupying the same or similar blocks of airspace, all looking for somewhere between FL300 and 340 (initially).
It's quite possible, even likely, that the track of the 94 crossed the 12's track at that most inopportune moment, despite having a comfortable cross track difference minutes earlier. It could just as easily have been any two aircraft en-route that night and probably occurs relatively frequently; without the media fanfare.