If you could guarantee a continuous shield over anyone, then there would be absolutely nothing stopping you and Allirea from walking in the front door and assassinating everybody you didn't like and stopping to paint each other's fingernails halfway through.
Not to mention the repeated references to painting nails whenever that strategy is brought up again.
Elspeth, at the end of a completely serious description of putting Edward back together.
[T]he ankle connected to the shinbone, this would be a terrible time to start singing -
"Honey!" Phil yelled up the stairs. "There's two teenage girls, a teenage boy, and a man and a woman here with what they say is good news and no visible scriptures! They know our names! I'm a bit confused!"