[Talisker]

Personally, I'm praying he never does.

That's an oxymoron. If you believe ex cathedra is divinely inspired and always correct, what is there to fear? And how can you pray that such a thing doesn't happen?

[Campion]

An ex cathedra statement is not "divinely inspired," nor (depending on exactly what you mean) is it "always correct".

The only claim is that is preserved free from error. (False teaching, in other words, heresy.) That doesn't make it prudent, nor does it make it the best possible way to teach "X" for any value of "X", etc.