An IME is a misnomer. The doctor is not 'independent.' It's a defense medical exam, paid for by the at-fault party's insurer, conducted by a physician hired by the defense. The exam is used to produce a report contradicting or minimizing the plaintiff's injuries.
Once a lawsuit is filed and the court orders an IME, the plaintiff typically must attend. Pre-suit, IMEs are not enforceable; you can decline.
We prepare clients for IMEs carefully. The exam is brief, the doctor is friendly, and the report nearly always says the injuries are minor or pre-existing. That report becomes evidence the defense uses at trial.