Look, we don’t mean to nag. But if there was ever anything worth nagging you about, it would be this: Obey the local laws of the country you’re visiting. An arrest or accident during a trip abroad can result in a difficult legal — and expensive — situation. Your U.S. citizenship does not make you exempt from full prosecution under another country's criminal justice system, and the U.S. government cannot bail you out. Many countries impose harsh penalties for violations that would be considered minor in the United States, and unlike the U.S., you may be considered guilty until proven innocent. Ignorance of the law is no excuse, so be informed. Go from here.
Keep track of the credit limits on your credit cards. Not only does this make good financial sense, but also good legal sense. Americans have been arrested for innocently exceeding their credit limit abroad. Ask your credit card company how to report the loss of your card from abroad. Keep in mind, 1-800 numbers do not work from abroad, but your company should have a number that you can call while you are overseas.
Take plenty of pictures, but only if you know it’s okay. In many countries you can be detained for photographing security-related institutions, such as police and military installations, government buildings, border areas and transportation facilities. If you are in doubt, ask permission before taking photographs.
Make smart purchases. Americans have been arrested for purchasing souvenirs that were, or looked like, antiques and which local customs authorities believed were national treasures. This is especially true in Turkey, Egypt, and Mexico. Familiarize yourself with any local regulations of antiques. In countries with strict control of antiques, document your purchases as reproductions if that is the case.
Make sure your prescription medication is not considered an illegal narcotic. If you are going abroad with a preexisting medical condition, you should carry a letter from your doctor describing your condition and medications, including the generic names of prescribed drugs. Any medications carried overseas should be in their original containers and clearly labeled. Check with the foreign country's embassy here in the U.S. to make sure your medications are not considered illegal narcotics. Find the foreign embassy’s website.
Don't accept packages from anyone. Some Americans think it's a good idea to take advantage of an offer for an all-expense paid vacation abroad in exchange for carrying a small package in their luggage. However, if you are caught, ignorance is no excuse. If the package contains illegal drugs or substances, the fact that you didn't know will not reduce the charges. You could miss your flight, your exams, or several years of your life during a stay behind bars.
Don't import, purchase, use, or have drugs in your possession. Drug charges can carry severe penalties, including imprisonment without bail for up to a year before a case is even tried. A conviction carries several more years of imprisonment in a foreign jail. In some countries it doesn't matter if you're underage either; you can still be charged as an adult. Mommy!
Do not carry weapons. Even a pocketknife can result in a serious weapons charge while on foreign soil - even if the knife is found during a search or arrest for an unrelated offense. Visitors driving across the border to Mexico should ensure that their vehicles contain no firearms, ammunition, or weapons – Americans have been imprisoned after one single bullet was found rolling around in the trunk.
Avoid participating in demonstrations and other political activities. Here in the U.S. we enjoy many liberties. However, political activities in other countries can result in detention and/or deportation by officials. Even demonstrations that are intended to be peaceful can sometimes turn violent, and you don't want to be caught in the middle. You can "stick it to the man," but on your own soil.
If you find yourself in a legal jam, contact the closest U.S. embassy or consulate for assistance. Keep in mind, U.S. Consular employees cannot arrange for local officials to release detained American citizens.