Star Wars: Rogue One - 10 Ways It Changes A New Hope
7. R2-D2's Secrecy
Throughout the early goings of A New Hope, R2-D2 is something of a painfully stubborn little spy, not sharing his mission of delivering the Death Star plans with even his closest companion, C-3PO. In addition, he tricks Luke into turning off his projector to keep him from seeing Leia's message, as well as sneaks off in the middle of the night to search for Obi-Wan and complete his objective. All of this, of course, is much to the frustration of 3PO and Luke.
However, given the events of Rogue One, R2's behavior now feels much more logical, especially from his perspective. Given the countless number of rebels who had just died on Scarif in the effort to steal plans, plus the ones who were slaughtered like fish in a barrel by Darth Vader while trying to get them to Leia, it's understandable that he would rather nobody know that he was now their custodian. And that means nobody.
Re-watching A New Hope with this in mind makes R2's behavior come off as smart strategy (despite his phsyical limitations), as opposed to just obnoxious stubbornness.