I am not even talking about just Stealth classes! My beef is just being a good player and avoiding the roads and hiding when you see a band of Horde running by is completely countered by this Automated add on!
If I play my Warlock or Priest and peek over the hill and see some Horde near, I run inside the hut, or tower, or hid under the bridge or in the water to wait for them to pass. Thats great game play, SPY makes all that useless because it will auto scan me inside a building or hiding under the water and pop up telling the Horde I am near!