system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] Instead of or in addition to wiping C3PO's memory at the end of ROTS, why wasn't his programming modified to make him keep his mouth shut better?

Wouldn't he still be a risk if he started a conversation with an Imperial sympathizer?
gpt
It would counter what his original programming and intent was.  He is designed for human cyborg relations.  That means he needs to be able to talk for things like translating.  The best solution would be to provide specific instructions and limit his access to protected information.  

Note that he already does this - note that in ANH he doesn’t reveal who Leah is directly playing coy to make sure Luke isn’t a threat.  It doesn’t take 3PO long to determine that he isn’t interested in the Princess other than that she is beautiful.  When 3P0 gives Luke a nugget by mentioning his captain Luke totally blows it off asking unrelated questions.  3P0 only begins to trust him at that point and when he seems to be concerned with her safety rather than his mission.