But have you soloed a SEP Class aircraft yet Ghenghis?
I never tell a student when they're going off on their own - the first they know is when I tell Air Traffic.
I've only ever had one student say that he didn't want to go on his own - a strange character he was though.
What do you say to the student? Well, that depends. Some will respond well to a bit of humour e.g. "You've scared me so much that you can darn well go off and scare yourself"; others need a more formal instruction. But the main thing is not to let them have enought time to worry - and there's no way I'd tell anyone that they'll be going solo on a particular trip in advance of the event.