It's even worse: Trump literally just promised during his midterm convention to pay everyone $5,000 should the Republicans win the midterms.
Note that this promise is itself illegal. It is a violation of 18 USC 597.
See: https://uscode.house.gov/view.xhtml?req=title%3A18+section%3...
That interpretation seems... odd. You seem to be implying that if your policy is to give everyone a tax credit (i.e. give them money) if you win then you're not allowed to tell anyone about it.