Well, I've had a couple of thoughts on how it might weasel around Summer's perceptions.
1. Red "reminds" Summer of her brother. Half her senses are screaming "familiar!" and the other half simply can't accept it because it's impossible. I kind of like this option because it's fairly simple and just leans heavy on people refusing to see what might in some circumstances be very apparent. It could even be that without Red's preposterous looking moustache anyone with half a brain could see the family resemblance - except that none is supposed to possible to exist.
2. Red's "hard to get a read on." I don't know of any mechanic out there to accomplish that without going somewhere with Force powers that Caros isn't after, but I suppose I could ditch one of Red's feats to pick up Strong In The Force or something and it could be a matter of "Red makes my head hurt" or "I like Red, but he's a little overwhelming." It's possible even that he wasn't like that before, only making that connection later on in life.
3. Red at least, doesn't have any equipment yet. Beyond his charming good looks and svelte figure though, I suppose that, given GM approval, Red could be in possession of some sort of "I'm really afraid of Darth Vader" anti-Jedi spooky senses tech. I think I recall something like that implied about in one of the Knights of the Old Republic games. It could be something from the time of the Jedi Civil War, a Sith artifact, or even a tool used by Jedi to fight the Sith I guess, as long as it blitzed the Jedi radar about the person carrying it around?
4. Red knows damned well who Summer is, and Summer's sense scream for him to be her brother, but he's absolutely denied it. Given all the other garbage that goes in and out of Summer's head as an unfiltered Jedi, and the fact that unconsciously every bone in her body says that he's familiar and family-ish, she just trusts the assertion because she's primed to trust him.
5. Summer knows who Red is, but Red doesn't. I'm not really in favor of this one, because I think it naturally lends itself to either a subplot that goes like this: Summer does lots of nice things for Red, Summer hangs a little on Red, Red has Luke Skywalker confusion when Summer pulls out her "I'm your sister, stupid" card. Or else it relies on Summer being real, honestly Jedi-ish in the vein of wise counsel moments like "It wasn't time, all will be revealed" etc. You know, something that Summer would have to pull a British accent out of her back pocket to pull off "on screen."
6. Summer and Red know that they are brother and sister, but no one else does. I think that this one would fly about as well as the similar Serenity plot point for the same reasons, Summer would have to never refer to Red with a familiar honorific and given the mentality I'm reading I don't think it would last very long and therefore it probably wouldn't be worth establishing as a secret in the first place?
7. Something else. I'm open to suggestions.
Now...I realize that a lot of these are sort of smarmy movie-ish devices and we're playing a game too. Unfortunately (fortunately?) my whole thing for PbP screams cinematics/plot, so I'm not really sure how well some of these would actually play out without, you know, a lot of weird media tricks to make them hash out with some proper pacing. Any of the "mysterious brother/sister" stuff, for instance, are sort of lame ducks if a single good die roll early on kicks the feet out from under them.
Anyways, I need to stop talking so I can get off to lunch.
