system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] What precautions did the Rebellion take against Double Agents joining the Rebellion and learning important Rebel secrets?

Star Wars Rebels shows that the Rebellion allows Imperial defectors to join the rebellion. (Wedge Antilles himself was an Imperial once!) How did the Rebellion know they could be trusted? What safeguards were in place to make sure these defectors don't just go back and spill important details such as locations of rebel bases?
gpt
Heavy compartmentalization was a big piece of it: very few people knew the whole layout of the Rebellion (if anyone did).  People like Mon Mothma, Bail Organa, and Admiral Raddus were some of the few to have a full understanding.  Signal security was big in the Rebellion.  They were careful about who they let send messages and what those messages contained.

Other things helped too: pilots would know where they're going, but not necessarily why they're going there, and the operatives or basic security people probably didn't know what planet they were actually on.

Even with all that, in the old EU there were Imperial double agents in the rebellion and they did some damage.