During filming of The Good, the Bad and the Ugly, the bridge explosion had to be done twice. The first time a miscommunication caused it to be blown before the cameras were ready. No idea how costly it was, though.

I once got a tour of ILM through a coworker -- this is a very real concern even with blowing up miniatures.

So you always make three: the one you plan to blow up, the backup, and the one you hope will go into the archives to show people later.

Is it that likely, as messing up the CGI? You could just abort before explosion if all your cameras don't look ok.

Some failures might not be obvious until the big red button has been pushed. What if the C4 in the cockpit is dud? What if the igniter at the wing spar is dud? What if the wires to the empennage have not been connected properly? What if the undercarriage collapses before the windows blow out? What if the vertical stabilizer's collapse causes a wind that exposes the hidden cameras from other angles?

This is fun, I should go on.

Please do!