Uh-oh... who said a flat cat can't get flatter? But I can't resist...
Passing the exam is just ONE of the requirements for registration as a PE. It may be the hardest requirement for most, but some people struggle with the application and finding enough references to document experience (the other major requirement for registration as a PE).
I am certain non-engineer graduates can pass the test if they prepare hard enough (it ain't rocket science!), but they still need the ABET accredited degree and/or experience. I'd also be willing to bet large amounts of beer that I could take *ANY* recent engineering graduate (any discipline!) from an ABET accredited school (say... RPI for example), tutor them for three months (assuming they remain dedicated), and watch them pass the Civil PE exam.
State boards need to carefully consider experience. I also think they need to remain restrictive on what they consider an Engineering discipline. (No software engineers for me!)