Denny, you have a good point. If the whole tow rig isn't free of all lost motion, toad will wander behind the coach. Every time it reaches one end of the slack, it bump steers the back of the coach. Then it bounces to the other end of slack and bump steers the coach the other way.
Hopefully, the Coach Hitch and Toad Base Plate are solidly anchored! Then, the Tow Bar has to mount to the Base Plate without any lost motion. If it has the locking collars like you mention, they have to be tight too. From there, the Ball Coupler (toad mounted bar) or Coupling (coach mounted bar) can't have slack either. The actual risk factor is if a Drop/or/Rise Adapter had to be used to keep the tow bar level. Adding that Up/Down device offers lots of chance for a sideways wobble in the tow rig. An expert (Eric Davis, Eric's RV, Sequim WA, developer of the Davis Tru-Trak bar for Class A RV's) told me as much as 1/2" of wobble can allow the toad to disturb the coach's tracking.
Both Blue Ox and Roadmaster offer wobble-eliminating clamps.