"...Are we going to tow it, or power it? Will it have nuke power plant? How fast can it go? What if, God forbid, the sailors on the ship need to see the shore line, for navigation? Have you considered that if the Phalanx fired and hit the steel decoy, the ricochets would pepper the ship? I don't know Admiral, I think you need to study this proposal a little more...."
Now you are making desparate, red-herring arguments.
Navigation is done nowadays with GPS. If the missile managed to hop the decoy (and you are assuming that the missile could know that the decoy is, in fact, a decoy...in itself unlikely, if the decoy was properly constructed), it (anti-ship missile) would be well above the decoy and the frigate...if the decoy was 50 meters from the ship (about 165 feet), the Phalanx system would have 0.2 seconds to acquire and engage the target. It seems like a stretch to believe that it would fire.
I know, now that we have this catamaran with 3" steel plate under chobham armor, let's mount a phalanx on it!
Oooh! Oooh! I know, let's move all of the weapons systems over to it! And the sailors, I mean, after all, the decoy is much better armored than the corvette, with the same armament, right? Then, we could use the corvette as the decoy!
%-)