Doing someone else's work?

I had an enquiry via my web site the other day from an international student asking if I would write their thesis. I'm not sure if this person was being naive, but I had to explain that it was normally expected that students write their own thesis (isn't that the idea of doing the study in the first place?). I'm happy to check through it once it is written - that is what a proofreader does. I'm not holding my breath for that work to come back to me, though!