Rinoa can't sleep when she's junctioned a GF.
She usually just lies still in the firelight, eyes on whoever's on watch at the time. Squall and Quistis both try to lecture her on how she'll slow them down if she's not properly rested, but that's easy for them to say, they can sleep anywhere. Selphie sometimes offers to hit her with a Sleep spell if it's bothering her that much.
Rinoa, worn out and aching and just wanting to sleep, usually says yes.
It doesn't help.
If she's junctioned, she spends the night drifting in and out of consciousness, her dreams filled with fire and smoke, the world boiling around her, buildings cracking and shattering into a million pieces that never touch her and someone laughing the whole time. It's impossible to breathe in without tasting the bitter-bright tang magic leaves in the air, and she's alone - she hasn't been alone since she left her father's house, and it isn't until she starts yelling for Squall that she realises that the one who's laughing is her.
Finally she turns to Zell and makes him take her GFs for the night - he tries to argue, but she's not on watch tonight and with her GFs as well as his own, Zell could probably take on anything that appeared without waking the others. If anything does show up, that night and any of the nights afterwards, she manages to sleep through it.
(She can still feel the magic prickling in her fingers when she goes to sleep though, like her hands had gone to sleep and were just waking up, and for that second when she closes her eyes she can still hear herself laughing -)