Secret silence through telling secrets

Sometimes, if you have a secret which might be found out through normal deductive reasoning by other parties, the best way to keep the wrong people from discussing it with you is to tell a few people with a spoken contract that states that they are not to tell anyone else (which they inevitably will then do).

Here is an example:

Cast

Jack - Your hero
Jill - Your hero's girlfriend
Barry - Your hero's good friend
Wanda - Your hero's good friends' friend.

Jack and Jill have a full disclosure sort of relationship and tell each other everything.

One day, Jack's friend Barry comes over and tells him a secret despite being under contractual obligation with Wanda -- the secrets' originator, not to. Barry delivers the secret to Jack, but only under the condition that he not repeat it to anyone else. In essence, Barry is using the same verbal contract that Wanda used with him, only Barry assumes that Jack will actually hold to it.

As stated previous, though; Jack and Jill have a full disclosure sort of relationship and they tell each other everything. So Jack tells Jill with the same contract, because their full disclosure relationship takes precedence over secret keeping unless the secret will directly affect the person who it might be told to, or someone close that she would be compelled morally to tell. Plus, Barry broke the contract to tell the secret to him, so it's only fair that he can do the same thing with others, right? So long as he tacks on the contract when he tells a few other people, he's not doing anything worse than what Barry did.

One way Barry can get around Jack telling Jill or anyone else about the secret, is to explicitly specify the parties that should most definitely, no matter what, not be told -- by name. IE, DO NOT TELL JILL, DO NOT TELL PACO, DO NOT TELL THE HOCKEY TEAM and so forth. With explicit specification, there isn't much wiggle room in the contract. Jack will probably not tell Jill, Paco, or The Hockey Team, unless Jack is a bastard -- and if Jack is a bastard, Barry should have known better to be telling him stuff anyway.

Jack is not a bastard though, so he does not tell Jill, Paco, or The Hockey Team. With of all this going on, an interesting thing of note happens:

Wanda, Barry, Jack and Jill all know the secret.

Wanda and Barry can talk about it.
Barry and Jack can talk about it.
Jack and Jill can talk about it.

Jack and Wanda cannot talk about it, because Barry told him and he has to pretend he doesn't know.
Jill and Wanda cannot talk about it, because Jack told her and she has to pretend she doesn't know.
Jill and Barry cannot talk about it, because Barry told Jack and Jack told Jill, but Jill isn't supposed to know.

If everybody knows who they're not supposed to talk about things with, no one will ever talk to Wanda about the secret, whether she knows that everybody is aware of the details or not. In fact, by letting out a secret in advance that may have been deduced by others later, Wanda has effectively shielded herself from discussing it due to a strange phenomenon that often exhibits itself in secret telling.

If A tells a secret to B, and B tells a secret to C, D and E, and then later, C and E discover obvious information that would have allowed them to deduce the secret on their own without the information from A or B (D didn't get it because he's a little slow) -- C and E will more often than not continue to put on the charade that they do not know the secret around A because of their obligation to B and his or her insistence that they not let on that they know, even though they know and everybody knows they know. You know?

And well, some other people can just keep a fucking secret.