From the spell Prying Eyes:
If an eye ever gets more than 1 mile away from you, it instantly ceases to exist.
Suppose a Wizard casts Ethereal Jaunt, then casts Prying eyes out to investigate the area within 1 mile of your location. The Ethereal Jaunt ends after a few rounds. The Wizard takes a seat and casts See Invisibility to be able to see if any of the prying eyes return to that spot on the Ethereal Plane, at which point he would recast Ethereal Jaunt, and go "collect" the eyes and view what they saw.
Would this work? Or is a planar boundary more than "1 mile"?