Always keep your recommendation up to date, in your possession, and posted near your plants. In personal use cases, many officers will not arrest you if you have an up to date written recommendation. If you are arrested, it is the best evidence to show to the DA, judge, and jury that you were a legit medical MJ user at the time. Do not let your recommendation expire because you may not be protected if you are arrested.
Medical MJ Cooperatives/Collectives
Under the law, there is a criminal exemption for patients and caregivers "collectively or cooperatively to cultivate marijuana for medical purposes." However, there is a misconception that one can sell medical MJ to others including cannabis clubs. This is not true it is against the law to sell MJ under CA state law. Telling the officer you only sell to cannabis clubs is no defense but a confession to a crime. Don't give a statement, and don't sell marijuana.
Medical Marijuana Caregiver
CA medical marijuana law protects patients and their primary caregivers from prosecution. A caregiver can posses, manufacture, and provide marijuana for a qualified patient in his/her care. A caregiver is defined as an "individual designated by the person exempted under this section who has consistently assumed responsibility for the housing, health, or safety of that person." Although "caregiver" is broadly defined,the law requires more from the caregiver then simply growing marijuana. The law requires legal caregivers to assist patients in personal health matters in addition to providing medical MJ. Help includes things like getting to health care appointments, shopping for food/personal care items, arranging safe housing, organizing social outings, gardening, pet care, and household chores.
Protecting Yourself as a Medical Marijuana User
Because compliance with the law is so important, take time to understand the law and to keep updated on new court decisions because the laws regarding "legal" medical marijuana use are continually evolving. Do not keep anything around that could be considered evidence of sales like Pay/Owe sheets, scales; packaging materials; pagers; photos of you with other illegal drugs or guns.