Bow rail doesn't matter one bit.
The law prohibits bow riding at ABOVE a wakeless speed. The intent of allowing it below wakeless speeds was for having people on the bow to assist in anchoring, mooring, etc.
Arizona law also states that no persons may be on the bow in a way to obstruct the view of the operator. No "wakeless speed" provision here.
However you may still be stopped if you are moving in the water with people on the bow if you are just cruising at a slow speed, not mooring, anchoring, aproaching a beach, etc.
The definition of Careless, Reckless, Negligent Operation, is "Any operation that may cause injury to persons or damage to property." We have the accident data to show that persons sliding off of the bow in a slow moving boat have been seriously injured and even killed from getting hit by the prop.
I can't figure out why, for the life of me, anyone would want to put people on their bow at all. Do you put people on the hood of your car when you're driving slowly? Allow them to sit on the window sills? Trunk lid? There's no law that specifically says you can't ride on the hood of your car. But do you thing the CHP is going to let somebody cruise by with someone there? I don't think so.
What's so different in a boat. If the boat builders had intended people to sit anywhere they wanted, they wouldn't have put seats in the boat. Or if they intended people to sit on the bow, they would have put seats up there. (Like a bow rider.
The "law" can't cover every idiotic thing a boater may do. That's why the Careless Reckless, Negligent" statute is there. There's a big difference between what is legal and what is safe.