She actually never drooled or had bubbles visible on the outside of her mouth, hers was a very mild RI that I caught in the very early stages (I would assume I caught it within the first couple days or so of her coming down with it).
All she had was the thick mucus sticky looking stuff in the back of her throat with bubbles around her trachea (I can shoot you over a photo that I took of the inside of her mouth if you'd like to see what a mild RI looks like if you PM me).
Since RIs won't clear up overnight (took a full 30 days to get my poor girl right again) I'd say to just check on them after they appear to be rid of the RI to make sure they actually kicked it.