You may not think that borrowing a loved one's credit card will get you into trouble, and you could think that using someone else's name to make an appointment is fine. However, if those people decide to charge you with a crime, you can face a mark on your record for participating in a federal crime.
If you're charged with identity theft, you could be facing serious time in prison as well as some high penalties and fines. Since 1998, the Identity Theft and Assumption Deterrence Act has been in place to deter the act of identity theft. The act amended the U.S. Code to make it a federal crime to transfer or use another person's means of identity when intending to commit, abet or aid in an unlawful activity.
In 2004, the federal government passed a second act to deter identity theft, the Identity Theft Penalty Enhancement Act. This act further penalizes those who use a person's identity to commit felony crimes like immigration violations or domestic terrorism. At least two extra years are added to a prison sentence for this crime, but five may be added for an act of domestic terrorism.
Identity theft is considered the theft of any kind of personal information, whether it's names, dates of birth, Medicare numbers, Social Security numbers, death certificates, passport numbers, passwords, biometric data or other kinds. Identity theft may also include Internet fraud, mail theft and credit card fraud. Both email and phishing scams are also considered forms of identity theft because they trick victims into giving up their personal information.
Source: Federal Bureau of Investigation, "Identity Theft Overview," accessed May 26, 2016