The critical concern is illegal activity.  Criminals will not be affected by prohibitions of any sort.  We see this in every instance from criminal nations to individuals.  Indeed, criminals take advantage of the rule abiding whenever possible.   If the concern about open carry is that some might be more willing to commit a criminal act, such as poaching, I can hardly see how this would affect anything as poachers would then simply hide their guns...  In short, I don't see excluding open carry as logically defensible.