specific permission of house of worship) Municipal mass transit vehicles or facilities Sterile areas of airports (sections of the airport located beyond security screening checkpoints, unless explicitly authorized) Non-government facilities with heightened security measures (Nuclear facilities, power plants, dams, oil and gas production facilities, banks, factories, unless explicitly authorized) Aboard aircraft or ships unless specifically authorized by the pilot in command or ship captain Private property where the lawful owner or lessee has posted a sign or verbally stated that firearms are not permitted Any public place, while under the influence of alcohol or drugs (including certain prescription or over-the-counter medications, depending on jurisdiction) "Opt-out" statutes ("gun-free zones") Some states allow private businesses to post a specific sign prohibiting concealed carry within their premises. The exact language and format of such a sign varies by state. By posting the signs, businesses create areas where it is illegal to carry a concealed handgun—similar to regulations concerning schools, hospitals, and public gatherings. Violation of such a sign, in some of these states, is grounds for revocation of the offender's concealed carry permit and criminal prosecution. Other states, such as Virginia, enforce only trespassing laws when a person violates a "Gun Free Zone" sign. In some jurisdictions trespass by a person carrying a firearm may have more severe penalties than "simple" trespass, while in other jurisdictions, penalties are lower than for trespass. Such states include: Arizona, Arkansas, Connecticut, Illinois, Kansas, Louisiana, Michigan, Minnesota, Missouri, Nebraska, Nevada, New Mexico, North Carolina, Ohio, Oklahoma, South Carolina, Tennessee, Texas, Virginia, and Wisconsin. There is considerable dispute over the effectiveness of such "gun-free zones". Opponents of such measures, such as OpenCarry.org, state that, much like other malum prohibitum laws banning gun-related practices, only law-abiding individuals will heed the signage and disarm. Individuals or groups intent on committing far more serious crimes, such as armed robbery or murder, will not be deterred by signage prohibiting weapons. Further, the reasoning follows that those wishing to commit mass murder might intentionally choose gun-free venues like shopping malls, schools and churches (where weapons carry is generally prohibited by statute or signage) because the population inside is disarmed and thus less able to stop them. In some states, business owners have been documented posting signs that appear to prohibit guns, but legally do not because the signs do not meet local or state laws defining required appearance, placement, or wording of signage.