My 12 year old daughter's school wants to give her in house suspension for passing a note. Please help stop it?

The ASt. Principal called me to tell me that My straight A honor roll daughter was being given 1 day of in house suspension for passing a note in study hall. In that note she drew a pic of a skinny girl and when her friend asked her who that was Theresa called the pic a skinny *****. I know it's wrong to write bad words, but she's never had a issue once in school. She volunteers for the school and is on their academic team that won 2nd place in the county this year. I told the ast. principal I would like to speak to the principal to overturn her decision. I even countered offered her INS with lunch detention. Am I wrong does my daughter deserve INS or should I fight it. The Principal is calling me shortly so any advice is greatly appreciated.