no universally correct setting for fsync

Someone just posted to the -admin list with a database corrupted
while running with fsync=off.  I was all set to refer him to the
documentation explaining why he should stop doing this, but to my
surprise the documentation waffles on the issue way past what I
think is reasonable.
 
http://www.postgresql.org/docs/8.4/interactive/runtime-config-wal.html#GUC-FSYNC
 
There are dire-sounding statements interspersed with:
 
| using fsync results in a performance penalty
 
| Due to the risks involved, there is no universally correct setting
| for fsync.
 
| If you trust your operating system, your hardware, and your
| utility company (or your battery backup), you can consider
| disabling fsync.
 
Isn't this a little too rosy a picture to paint?
 
-Kevin