A really simple test to prove whether or not the pelican striker as shown in the photo will reduce tip movement is to remove the bow to pole tip lines, while keeping the pelican striker setup normally, and then try to move the tip up and down.

Looking at the original photo, it appears as though the whole pole with pelican striker will pivot about the main beam connection, just like a normal pole without pelican striker would do.

If the pelican striker wire went through another "spreader" under the dolphin striker and continued to somewhere like the rear beam, then it would influence the tip movement because the pivot point of the pole is separated from the wire. This is how skiff poles are setup.

What the pelican striker does at mid pole is another matter and probably more to do with the jib than the spinnaker.