I never understood this tactic. Not being a rook and not having seen the current map I can't comment specifically to that, but in general to having seen this before myself it seems... wrong. CV's should be offensive tools primarily and defensive if your under attack, i.e. the horde is rolling base after base down your coast. A cv popping up next to your base can add an edge. Loosing a CV isn't terrible, but having one and never using it is IMO.