That's plausible enough, too.
But it's not like the lie they were all telling needed to be plausible. It was a pretty easily blown-open lie. Vader never believed it. He was right not to.
This movie doesn't change that at all. If anything, all it does is make the rebels more defiant.
I mean, look at Leia selling "I don't know what you're talking about" now. She might as well be saying "suck my fuckin' dick, I ain't giving you shit."
Nah, she's saying "We don't have the plans, we're on a diplomatic mission." She's lying. Vader obviously tracked them through hyperspace somehow. Someone brought up some sci-fi bullshit earlier in the thread about hyperspace buoys, which sounds good enough for me. I know in the Radio Drama version of this, they get the plans beamed directly to the ship, and immediately jump, and think they're safe, only to drop out of hyperspace at Tatooine, and almost IMMEDIATELY get rushed on. So far as I can tell, there's no version of this story in which they don't immediately get got after dropping out of Hyperspace.