Originally Posted by
onthesam
An FYI (I was looking for this answer recently and did not easily find it):
It works in the reverse as well. You can access T1 with a T5 BP. Great for visiting Polaris Lounge before *A T5 flights if you've got the time.
So that's a perfect scenario of when this would be applicable and I would argue very worthwhile. Especially if it's an airline that participates in precheck. You get a full precheck line, the polaris lounge (or any regular lounge for non longhaul J/*G), and you have the opportunity to take the shuttle bus over.