Why is that when i am stealthed and i'm far to medium range of an enemy they can shoot me easily (nano vision off and sometimes even when i'm sprinting) as if i am not in stealth and i have stealth enhance 3, but on my view i can barely see stealthed enemies up close and i have to use nano vision alot! Does it something to do with the brightness of my display (i have mine at 50), or do i really have bad eyesight? It is really frustrating to see enemies shoot me down when i'm in stealth with so much ease.
Tag hack or you just run into some good players.
Tag hack allows players to see opponents nicknames displayed above their heads, its like you can see your teammates nicknames just in this case they also see opponents nicknames. Sadly this hack is undetectable and you can't prove anything.
Other this is that there are people who actually are good at finding people using cloak, it's not so hard to spot cloaked player, especially if he run near any light source. Also if someone put crosshair on you he will see your tag displayed above your head.
Also cloak tracker at lvl 3 show cloaked players.
Last this is ... being a victim of Visor tagging

Someone tag you with visor and other people know where you are.