The statewide general definition for snagging: Attempting to take fish with a hook and line in such a way that the fish does not voluntarily take the hook(s)in its mouth. (Page 13 2000/2001 fishing rules Washington)

Sounds to me like lining is a more subtle way to snag. I agree that we all may have done it at one time or another, but that doesn't make it something different than snagging.