Nothing to this effect in either of our car manuals (1914 Prius and 2005 Sentra) and I have read through both of them, with particular emphasis on the section on safety. There is nothing in either manual about using the headrest as an escape tool. This sounds like sliced baloney to me...Why would anyone develop a safety feature and then not mention it?

In real world terms, how significant would such a feature be. How often would one be able to use such a feature?