That's understandable but there are a few problems with this. Okay, in Squall's mind, they have never met before, and Rinoa just used her finger sign instantly like a finger snap. I'm looking at this FMV right now, once she saw him for a second and then used her finger sign like the whole world has came to an end. Did she ever use finger sign with other people? Nope, only Squall.

During his flackbacks, when she used her finger sign repeatedly, a few second after that.. a splitting image of Ulti just came up. That's just ironic.

And in the end, you see the garden first, then Rinoa and then when she used the finger sign, Squall just came out of no where. I've been trying to find out whether Squall was there before Rinoa used her finger sign but it's hard to tell at the moment.