dangerously dedicated physical disks.

[atar]

Hi there!!

During the reading of the FreeBSD handbook, I've encountered at the term  
'dangerously dedicated' regarding physical disks and the author of this  
chapter in the FreeBSD handbook didn't think this term need more clarity.  
so for newbies like me in the FreeBSD world I want to ask: what's the  
'dangerously dedicated' term meaning by?

Thanks in advance!

atar.