That’s a big trackpad. The trackpad on the 13-inch model is more
than half again as big as on its predecessor, and on the 15-inch
model it’s doubled in size. As Phil Schiller said on stage
Thursday, Apple can make the Trackpad bigger now that it’s a Magic
Trackpad rather than an older hinged model because even at large
sizes the entire surface is clickable. (The previous generation of
MacBook Pros finished life with Magic Trackpads, but they were
tucked into the space designed for older, hinged models.)
The trackpads are large enough that Apple has had to build in more
palm-rejection intelligence, because when you’re typing on these
things, you’re going to inevitably slide your palms across them.
In my experience writing this article on a 13-inch MacBook Pro,
the palm rejection worked well — I never felt that I had to
change my typing approach just to avoid weird mouse movements.
I’ve been using a non-Touch Bar review unit since last week, too (to my knowledge, no reviewer yet has a Touch Bar model), and I’ve had the same experience with the bigger touchpad, which is to say no problems at all with palm detection.