I. It shall be a violation for any person to cover, remove, deface, alter or destroy any sign or other marking identifying a drug-free zone as provided in RSA 193-B:4, I.
II. Lack of knowledge that the prohibited act as defined in RSA 193-B:2 occurred on or within 1,000 feet of school property shall not be a defense.
III. A violation of RSA 193-B:2 shall not include an act which occurs entirely within a private residence wherein no person 17 years of age or under is present.