When Is It OK To Bail Without Calling?

So, a friend of mine was recently ditched, without warning*. So it brought up the question, when can you bail on your date without so much as a call or text? And here are my scenarios:

1. Somali pirates expand operations into your region & you are captured, but you'll need CNN/BBC footage to back your claim.
2. The inevitable zombie apocalypse started in your neighborhood and you spent the day beheading/debraining the undead. Again, footage.
3. Your super-hero alter ego was called away to fight Dr. Colossus. No footage necessary, but taking your ditched date for a flight over London (or any major city) will balance the scales.
4. Your dog had rabies and it needed to be shot, Old Yeller-style. This one will require documentation from the authorities and witnesses of you crying while pulling the trigger.
5. Anything that killed you, but the polite thing to do is a quick haunting to show you care.

* Though the dipshit called 2 hours earlier to say he'd be there.