Jay is correct. The only place where a compromised frame [for pan-and-scan video transfers] is used in Cameron's films is where digital visual effects come into play. These effects shots were composed for a 2.0:1 A/R, so you'll see obvious panning and scanning in these shots. Why not do effects for the full Super 35 frame? Cost. It is much cheaper to do effects for only the part of the frame that is seen in theatres than for the full Super 35 frame. You'll notice if you watch T2 or Titanic in the "fullscreen" version [hate that term] that the top and bottom is opened only slightly for the effects shots, but you'll see much more of the top and bottom of the frame in non-effects shots.

As for Kubrick, I'm almost certain that if he'd seen what today's hi-def displays are capable of producing, he would have authorised video versions of his films with both open matte and matted transfers.
Note: E.T. was not open matte. Allen Daviau shot with a 1.66:1 hard matte in the camera and composed his shots in a loose 1.75:1 A/R.