the only thing clipping fins does is add some sent to the water and makes the bait swim more erratic. the fish love this.....
If you fish with big baits or are going to try fishing with big baits and are worried about false flags, here is what i do on all my big bait tip-ups. I use polar tipups (both thermals and original) that have T-bars that hold the flag down. All I do to prevent false flags is wind a rubber band around the notched side of the t-bar to create more of a lip for the flag to have to be pulled across. I also use this method when i am using regular sized baits for bass and pickerel and perch when there is alot of wind blowing across the ice.
this can be done to the wooden old-fashion tip-ups also all you have to do is tie the rubberband or wind it onto the arm that holds the flag.
If you dont have rubber bands you can also tighten the nuts found just below the spool of your tip-ups or the nut that is at you T-bar.
You can also smack the sucker lightly on the ice to stun it and it will quiver under the ice.
Good luck,
JiggerMan