> "expect an annual failure rate (AFR) of between 0.1% –0.5%, where failure refers to a complete loss of the volume" Well, I think the OP has just experienced a sample from a probability distribution characterized above.
EBS is either reliable or not. You cannot be a little pregnant.
Even the OP's metaphor is broken! The saying "you cannot be a little bit pregnant" may be traditional, but it too is only an approximation. There are these things called miscarriages. They happen all the time, often before a woman realizes she is pregnant. Then there are the false pregnancies:
http://en.wikipedia.org/wiki/False_pregnancy
And these are just the common edge cases.