I know someone who was nearly killed by a steel fork's failing. Can you say "metal fatigue"? I don't trust cheap carbon. I also don't trust old steel with miles on it.
Anything built by man (or woman) can and will fail at some point and with enough force exerted against it. I also know someone who totaled a ti frame against the side of a car. Strange but true.
2007 Seven ID8 - Bontrager InForm
2003 Klein Palomino - Terry Firefly (?)
2010 Seven Cafe Racer - Bontrager InForm
2008 Cervelo P2C - Adamo Prologue Saddle