as far as I've always been aware - orange means STOP !
I remember this, from way back at school when we had cops come in and teach us the road rules
obviously, if it turns orange and you don't have time to stop, you don't have to try to skid to a stop, but as far as the "rules" go....orange means stop and you should (if you can).
So, I think she would be in her rights to book you for it if she really wanted to (harsh call tho!!)
As for a fine "in the mail"....I've been booked and it arrived in my letterbox. Personally by a patrol car too, cos there was no stamp or mailing stuff on it