Zumwalt has a Wavepiercer bow, i.e. it is not safe to be on the foredeck at sea. Why should there be rails, if nobody should be there? I guess that the foredeck cannot be accessed at sea on many ships.

Many European frigates have foredecks without rails. The handling is done anyway one deck lower.

E.g. Niels Juel:






Niels Juel in Korsør