Because yellow LCD's are defects. They should all have the perfect blue hue.
While I agree 100% would that be something you could adjust?
My wife's 3GS is so yellow I can't believe it ever made it through QC so trust me yellow sucks!! I have a 3G I use for work and iPhone 4 I use all other times and both screens are great but her phone is HORRIBLE!
how do you know if you have a yellow screen? Mine looks pretty good, but my brothers phone looks sharper..
If your screen looks yellow...you have a yellow screen.