Lie? No. Polite rejection is usually understood by people. They do know that you are using a formula. That is basic socialization. Most people know that people aren't literal.

And that is why people who won't accept a rejection keeps pushing.

But the escalation of rejection is not only about saying no bluntly. That is the "midle", for the people who only understand literal. There would be a "No, thanks", Then a "no". Then a "I've already say no". And after that, it would keep escalating to explaining why not, which is usually hurtfull. By that time, even the ones who won't take no for an answer would be calling me a bitch. But it gets the message across.

What is twisted is that some men play victim when we have already rejected them politely because we haven't rejected them in a way they deem aceptable for their ego when a "No, thanks" should be more than enough. And let me add that "No, thanks" is perfectly clear. The only reason to insist after a "No thanks" is to push the other person.