Should unreachable code be considered an error?

[Bernard Helyer]

I asked the Ars forums ( http://arstechnica.com/civis/viewtopic.php?
f=20&t=1153378&p=21965411 ) and I ask the same of you: should 
unambiguously unreachable code be an error or a warning? ( see the linked 
forum post for more details ).