Lucas afirmou (em uma entrevista publicada em Revista Empire Edição #156 (junho 2002) que ele pretendia que o público não soubesse se Vader estava dizendo a verdade até assistirem ao terceiro filme.
Lucas claims he had the notion in mind from the start, but the idea
didn't appear until the second draft of Empire, and in the first there
is the contradictory appearance of a different father (a ghostly
presence like Kenobi). Lucas also wrestled with the idea of keeping
schtum on Luke's parentage until the end of the third film, but
eventually found the perfect moment. "I conceived it so that you would
not know if Vader was lying or telling the truth," Lucas said. "You
have to have an escape hatch for kids psychologically so they can deny
it."
Note também que Lucas, no filme novelização oficial (publicado no 1980) tem as mesmas preocupações, para começar, que Vader pode estar mentindo. No final do livro / filme, ele praticamente aceita que Vader é seu pai e está mais preocupado com o motivo pelo qual Ben não contou a ele.
Luke’s mind whirled with those words. Everything was finally beginning to coalesce in his brain. Or was it? He wondered if Vader were telling him the truth—if the training of Yoda, the teaching of saintly old Ben, his own strivings for good and his abhorrence of evil, if everything he had fought for were no more than a lie.
He didn’t want to believe Vader, tried convincing himself that it was Vader who lied to him — but somehow he could feel the truth in the Dark Lord’s words. But, if Darth Vader did speak the truth, why, he wondered, had Ben Kenobi lied to him? Why? His mind screamed louder than any wind the Dark Lord could ever summon against him.