No, this is not a joke. Swedish doctoral students go through a “pie-throwing seminar” towards the end of their doctoral process. (We in Finland call it a “manuscript seminar” or a “mock defence“, which is not half as funny as throwing pies.) But the idea is the same, getting critical comments on a thesis just before the final work shall be submitted. The more critical the better, as this is still the time when changes can be made. And who wouldn’t prefer to receive constructive criticism instead of a destructive verdict in the end?
Gyöngyi
BTW, there is even a book on focusing on your viva from the beginning, Trafford and Leshem’s (2008) “stepping stones”, which tackles the same idea from a UK perspective.