Caroline has used somewhat unethical methods in her political battles in the past (lording over Cavendish after her "tryst" with him & Major Treadway), and she holds a great secret about George and a number of his … paramours. One wonders if she will stoop to using that weapon in the war with George.
She may not be aware of the Brotherhood, of which George is a member (along with one of the princes!), their common commitment, effectively, to disposing of people who threaten them with exposure, and thus the danger to herself if she should make such a threat. If George forces her into a corner too suddenly, she might attempt it rather than surrender, unaware of the potentially dire consequences.