The best way is to never tell anyone and if you know something and its not your business, forget about it. If you can. They couldn't trust anyone. They didn't know if their neighbours, friends or anyone else would, or someone else would tell the Germans . A secret is not a secret if more than one knows.

The big problem is, they can't keep their mouth shut. They have a tendency of say things without thinking first. I guessing you never thought about about that

She grew up in a large rural family. I was understood never tell any secrets to the younger siblings, better yet don't say anything. The kids may have accidentally said something, that could very well get people shot. Best to not tell them anything. For that matter don't tell anyone.

My mom would say, drunks and children tell the truth. I guess that she would have known, being that she had lived in Holland during the German occupation.