Pull-buoys, kick boards, fins, and paddles

Pull-buoys, kick boards, fins, and hand paddles are not allowed in the competition pool or warm-up pool. This statement is always included in the “Warm-up Procedures” under the “Meet Information” of all Nationals (and is enforced in many of the local meets). I have looked in the USMS Rule Book and was not able to find a rule(s) that bans any of the above mentioned items from warm-up at meets. Rule 102.4 covers Warm-up/Warm-down procedures (Availability and Procedure) and Rule 104.5 covers the warm-up schedule (under Conduct of the Championship Meet), but neither specifically rule bans the use of pull-buoys, kick boards, fins, and hand paddles. The rule book index offers no further help (“Safety” offers no help). If there is a rule banning these, where is it?