This is usually when I need to just do a rectal or breast exam. To be totally risk free you always use chaperones. Even that won't protect you from a charge by a psychotic patient. It depends on your tolerance for risk. The safest tact would be to video tape every encounter.
Some docs do that, especially in critical consent situations.
To me that is an intolerable intrusion on the patient doctor interaction. I've been in solo family practice for about 20 years. I use a chaperone consistently. If the physician chooses not to follow that policy, they have to document with each patient whether or not they have a chaperone with them. Without exception during the last 20 years, can state I have never done a breast or pelvic examination on an adolescent or adult woman without an assistant.