I agree with you overall but I'm not sure the Trump bet is the best example.

He certainly isn't going to be thrown out of office (unfortunately) but those 16% of bettors also win if he dies this year, and he's 80, fat, still gobbling burgers and shows signs of someone that has had at least one stroke so far.

On the other hand he has access to the best medical care, but even still a 16% chance he drops dead before the end of the year isn't that outrageous.