Exactly. If that were a gift from him (plausible, as it's jewelry, and it looks like the Greek cross) and she wore it, it's a sign to him.
Here's my theory: As far as FD knows, she's giving up info on him/blaming it all on him. Perhaps she considered that, and then reconsidered. So she gave LE a "tip," pretending to offer something to them that caused a search of the reservoir again recently - she figured it might take a while, but it came up empty, quickly, and LE said "you're just playing with us. We're done with this." Hence her sadface.
She wore the gift from FD (my supposition, not given fact) and
signaled him with her hands at least 4 times - knowing photos were taken of her in court, and outside.
This was not a signal to her daughter - she can text/call/video chat with her daughter. She's NOT, however, supposed to contact FD - so, how does she do it? Via the media.
Why would she do this hand symbol that indicates "peace" or "two/together"? To show she's in it with him, she's not giving up info on him, they are "in it together". Or perhaps they had prearranged a symbol as FD had prearranged words (e.g. "hardware") and alibis.
I think she knows she's in it deep and perhaps so deep that she CANNOT give up more info.
Is this insignificant? I don't think so. I think it's major that she didn't even TRY to hide it.
Again - take a look at the photos - other observant people noticed other times she
went out of her way to make this exact symbol with her hands during this hearing:
From the SA:
https://s.hdnux.com/photos/01/05/57/67/18283980/31/1024x1024.jpg
https://s.hdnux.com/photos/01/05/57/67/18283985/31/1024x1024.jpg
(All moo.)
edit: fixed "him" -> "her"