When I was 19, I had a credit card with a 7K limit*. I spent up to 2K over a year in college, and then my mom confronted me about it and offered to hold onto it so I could only use it in emergencies. She even offered to pay the monthly bills if I promised not to get another card.
Two years later, I found out that she maxed it out by ordering stupid shit online in my name. She stopped paying the bill for some reason and the total I owed went up to like 11K.
*Yeah, I know. No one else I know was given that sort of limit at that age. Weird...