Dishonesty is Trump's hallmark: He claimed that he had spoken clearly and boldly against going into Iraq. Wrong. He spoke in favor of invading Iraq. He said he saw thousands of Muslims in New Jersey celebrating 9/11. Wrong. He saw no such thing. He imagined it.
Dishonesty in trailers is more than a moral issue, it's a practical one. If you don't deliver in the film what you offered in the trailer, you'll get bad word-of-mouth.
Dishonesty of any kind will create a blemish.
I'm a guy who is easy to get along with, and I'll put up with a lot of things. But not dishonesty.