There are subtle tricks of memory that can be played, not only with electronic beings, but also organic brains. If a living brain can be hacked to implant or suppress memories, then almost anything becomes possible. And when it's possible, you can use it in a game to interesting effect. Just look at Total Recall for some possibilities.

Transcript

C-3PO: I don't even understand how you got the Lost Orb.
R2-D2: I calculated the exact trajectory after the Peace Moon explosion. It was a simple matter of being in the right place at the right time. A subtle tweak to Luke's flight path leaving Yavin a week later to intercept the orbit, and bingo. C-3PO: How do you do these things?
R2-D2: I am an astromech droid.
C-3PO: And why didn't you tell anyone?
R2-D2: I was fighting off Nute Gunray at the time. I had to make myself forget until the right moment.
C-3PO: Well, I'm more comfortable with you having the Orb than Nute.
C-3PO: Remember Artoo, with great power comes great responsibility.
R2-D2: I'm very responsible! When they ask who electrocuted every single meatbag in Jabba's palace, I will graciously admit that I was responsible.