I don't even know of this mythical NLV open carry law everyone keeps talking about on the Internet (Granted, I've not bothered to waste time looking for it either). I open carry in NLV frequently, as do many of us.
If this law exists on the books (like their weapons in vehicles law), they are in full knowledge of it being preempted by state law. The vehicle law has only been attached to people pulled over for other offenses and otherwise act like thugs. I've never heard of it even mentioned to normal people.
Enjoy your visit!
Do NOT carry a baton in the state of NV.
EDIT: In reviewing www.handgunlaw.us, I think this is where everyone is getting it. I will write to Gary and see if he can reword it. He even only cites the weapons in vehicles ordinance when mentioning carrying of firearms in general.