If you are getting this from the dealer, I think there is a high probability of agency risk. The dealer tries to do what they can to get you signed up, and earn their commission. Later, when your partner files the claim, the insurance company goes over all the details with a fone-toothed comb, and either denies the claim for some deficiency in the application that is irreversible (e.g. a doctor's note) or makes the process so onerous as to not be "worth it." Also, if paid off, there may be conditions about not selling the vehicle for some time, so as to collect the equity in it.
Personally, I would not do it anyway. You give a lot of facts that you are well off, but want to try and take advantage of a financial mechanism. At the very least, though, it's your partner who may be stuck with an expensive truck they have to pay off. Is it something they want, or something you want? If it's just for you, consider a 1 year lease.