I am LIVID.

My parents went on a cruise for a week, so I'm in charge of the house and my younger siblings. A few nights ago, my sister who is 16, told me she was going to a friends for a cookout and I said that's fine. She doesn't have her license or a car and didn't ask me to take her, so I asked how she was getting there. She told me they were almost here to get her, so I went on about my business.... Well tonight, one of her friends asked if I had heard about her experience and I said no. She told me that she had taken my dads truck and got pulled over for not having her lights on at night and wasn't able to give the cop a license cause she DOESNT HAVE ONE. She got a ticket! Is it wrong of me to tell my parents before she does? I AM NOT getting in trouble for her idiotic, irresponsible decision. She lied to me!!!! I am PISSED. She has no idea that I know. UUGGGHHHH.