Punishing a child twice

My sister's daughter is sixteen and was caught drinking with her older step sister, who is twenty-four. She was reprimanded by her father and her step mother. My sister recently was told by her son about the incident and was talking to me about it. She thought she should take her daughter to task about it. I told her that would be harming her relationship with her son because it may get him into trouble with his sister. I also expressed that her daughter was already punished by her father and step mother. I felt that by her also talking with her daughter about it would be a case of double punishment. I suggested that she just sit down and try to have an open discussion of drinking with her daughter instead. Should a child be discipline twice just because one parent was omitted from the decision process?

While it is sad that both parents could not be involved in the disciplinary process, it is probably a good idea not to have the daughter punished a secondary time, but, as suggested, begin open conversations with her about the dangers of drinking. Another suggestion would be to have the parents have a serious discussion about why a 24 year old is permitted to be hanging out with a 16 year. It sounds like some boundaries need to be worked out with the parents if at all possible.