It's called a half-pin, since one of the two men (Knight or Queen's Pawn) is pinned against the King. I would only move the Rook's Pawn if it gains me something... although that "something" might just be the future option of kicking the Bishop again with the Knight's Pawn.
h3/h6 or a3/a6 should not be an automatic reflex.
I was thinking about the common early bishop pins on knights and wondered if playing a3 and h3 should wait? Does this transfer the initiative since white reacts to black, or does it stay with white since it forces the bishop to move or an exchange?
If black moves the rook's pawn and white retreats, does this give black the initiative, such as in Ruy Lopez?
In the Ruy Lopez, can Bb5 really be called a pin on the knight? Isn't it more of a threatened pin, and therefore could be called a pin on the queen's pawn?