I don't buy any of these "I own my Modules" defenses. Get over yourself. There is a whole brave new world of open source development. The days of code based Intellectual property is slowly diminishing.

That said, if a client has contracted for a project I would not give them anything until they have paid in full. In fact, we present the code to the client, as part of their system information packet at the time of training. Training doesn't take place until full payment has been received. This is all explained to them ahead of time.