"I am very busy, please stick to the course material."
I wonder if the professor has it configured to learn from the student's questions? Will the bot turn into a promiscuous neo-nazi a week into the class?
The software worked remarkably well in this instance because the system was well constrained, and the students weren't on the lookout for it. If they do start quizzing their new unseen TA (Dr Colin V Olutionalnet) on random trivia it could presumably deflect the query or have a few canards pre-programmed.
For example, if a guy is able to answer questions at all times of day, really fast, they're either an AI or Jon Skeet.
Also, real TAs have a life outside of the course. What will an AI say when you ask them whether they enjoyed last night's episode of Game of Thrones?