My bad.
On another topic, why wipe just 3PO and not both 3PO and R2? R2 knew of Luke and Leia being related as well as Anakin turned into Vader.
Because R2 is smart and loyal. He wouldn’t say anything and the empire wouldn’t think to extract his memory if he looks like every other droid.
C-3PO has been shown repeatedly willing to flip sides if it means survival. A single threat and he’ll let it all out. He’d spill the beans to Luke in their first conversation.