Are these states that voters could "cross over" in the primaries and send Madam Benghazi packing?
NH is a state that same day registration. So, to answer your question yes. I have personally seen people go in as an Independent or Undeclared, ask for a Democrat ballot and then change back to Undeclared after they vote.
IMHO, this is BU((CR#P. This was changed about ten/fifteen years ago because they said it would increase the voter participation rate in the primary. All it did was make the winner of both sides more middle of the road.