You really shouldn't be worried about ghosts
Because, to be perfectly honest with you, I would be worried about creatures that live in the Ethereal, especially Night Hags and the Sahkil.
While ethereal is also incorporeal, the opposite is not true. There is little to be confused here, an ethereal creature is either fully or partially touching the Ethereal Plane, as such, you shouldn't be worried about incorporeal creatures (like ghosts), but other inhabitants of the ethereal plane that will surely be able to notice you blinking around.
Do notice that it's obvious when a creature is ethereal, or merely invisible, as pointed out by See Invisibility. And while ethereal creatures are normally invisible to those who are not ethereal themselves, the same cannot be said by all incorporeal creatures (despite what the book says), most of them are perfectly visible (such as Allips) even without the help of spells.
Ethereal creatures are invisible. Since ethereal creatures are not materially present, Perception checks, scent, Blind-Fight, and blindsight don’t help locate them. Incorporeal creatures are often invisible. Scent, Blind-Fight, and blindsight don’t help creatures find or attack invisible, incorporeal creatures, but Perception checks can help.
Most ghosts cannot truly hide in plain sight, and will be visible if they don't possess some ability to become invisible (look up the Frightener ability). Do note that while ghosts can be found in the Ethereal Plane, those are not exactly in the Material, and cannot affect creatures in the Material, unlike those ghosts in the bestiary and often found in adventures.
You cannot be attacked in the Material Plane by a ghost who happens to be in the Ethereal Plane. But you surely could be attacked in the Ethereal Plane by any inhabitants of the Ethereal Plane, which includes the brief moments that you Blink into the ethereal plane. For this shifting to happen, the creature needs the ability to travel between the planes, like a Phase Spider, which the common ghosts do not possess.
To put it simply, if you blink, you shouldn't be worried about the ghosts you have already seen, but the ghosts you didn't know about that were nearby in the Ethereal Plane.
Developers Clarification
The weirdness you noticed in the Blink spell is a bleed from previous editions, as pointed out by James Jacobs (Creative Director). For the developers, however, there is a clear distinction between incorporeal and ethereal.
In Pathfinder, we've attempted to draw a hard line between the two states, but there are places where the old language still bleeds through. Blink is one of those cases.
They are different things for different purposes, and ghosts were changed during the conversion from 3.x to Pathfinder on purpose, as pointed out by James Jacobs again, so they do not exist simultaneously on two planes at once.
For the most part, you need to go to the Ethereal Plane to fight creatures there. Pathfinder has deliberately pulled away from the idea that monsters can exist on both the Material and Ethereal Plane at the same time—ghosts, in particular, have NO connection to the Ethereal Plane at all.
Furthermore, being incorporeal does NOT mean you're ethereal.
