MYTH: You have to be over the legal Blood Alcohol Content (BAC) limit in order to be charged with Driving Under the Influence.
FACT: In most states, it's illegal to drive a car while "impaired" by the effects of alcohol or drugs (including prescription drugs). This means that there must be enough alcohol or drugs in the driver's body to prevent him from thinking clearly or driving safely. Many people get to this point before they are at the BAC limit, which is now .08% in all states. That means that someone who is not at or above the legal limit can still be charged with a DUI if their ability to operate a motor vehicle has been impaired.
MYTH: A written contract can't be broken.
FACT: Actually, parties can get out of written contracts in many ways. For instance, if the contract wasn't created adequately, courts will declare it not to be binding. Also, a contract is unenforceable when the terms are unconscionable - in other words, when the contract is patently unfair to one of the parties. The actual terms of a contract might also contain conditions under which the contract will be dissolved.
MYTH: If someone breaks into your house, you have the right to use lethal force against them.
FACT: While most jurisdictions protect a homeowner's right to defend their family and their property, not all that do allow the homeowner to use lethal force. Moreover, even jurisdictions that do allow for the use of lethal force require that the homeowner reasonable believed that the intruder meant to inflict death or serious bodily injury on them or their family.
MYTH: An error on a traffic ticket voids the ticket.
FACT: This isn't usually the case. For minor errors, there are administrative procedures that courts can use to modify information entered on a traffic ticket.
MYTH: If the police don't read a person their Miranda rights when arresting them, they can't be convicted of the crime.
FACT: We all know that police are supposed to advise an arrestee of their right to remain silent and their right to an attorney, but the failure to do so won't result in the case against the arrestee being dismissed. Instead, a judge might not allow any statements the arrestee made while in police custody to come in as evidence against them. This might make it harder to convict the person, but they could still be found guilty if there is sufficient alternative evidence.
MYTH: If a person is driving a car without a license and is injured in an accident, they can't recover damages if the accident isn't their fault.
FACT: Whether or not a person is driving with a license won't affect their recovery if the other driver was at fault.
MYTH: Couples who live together for six years are considered married.
FACT: Not all states recognize "common law" marriages, and even the ones that do have additional requirements. The amount of time that a couple has cohabitated is not the sole determinant of whether or not the couple has entered into a common law marriage.
MYTH: Car insurance won't cover you if someone other than your spouse or a family member is driving your car.
FACT: Many policies actually will cover you in these circumstances. Check with your insurance provider to see if your policy includes this provision, or, if it doesn't, whether or not you can add it on.
MYTH: An undercover police officer always has to admit that they're a cop.
FACT: Police officers are allowed to use deception to fight crime, as long as they don't intimidate or harass someone into committing a crime that they otherwise would not commit. If police officers had to reveal that they were cops it would put their lives in jeopardy, so there is no requirement that undercover officers reveal themselves when asked.
MYTH: Every nonprofit (and every donation to a non-profit) is tax-exempt.
FACT: In order for a nonprofit to gain tax exempt status, it must fit the requirements of Section 501(c)(3) of the U.S. tax code. Donors who make a qualifying donation to a 501(c)(3) organization are entitled to list the donation as a deduction, but donations to groups that haven't been granted tax-exempt status under 501(c)(3) are not tax deductible.
This list comes courtesy of Kevin Fayle.