[cashflyer]

Ok... let's look at this from a different angle.

What's in it for you? What do you gain by participating in the exit interview?
Is there a severance package hanging in the balance? Is there a Letter of Recommendation that you need? Etc. If there is nothing to gain, then I would say you are under no obligation to participate. Politely decline and move on.

Or participate and just do like you say everyone has been doing all along - sit there and blow smoke up their asses, then go get some good coffee.