"Unsure" return codes

[Tom Allison]

What are the (valid) return codes if you are using a ternary measure of 
Yes/No/Unsure and you are not using '-e'?

I got badly burned yesterday on razor-check when it started returning 
error codes (exit_code > 1) and I started generating duplicate emails. 
(OK, not the best rule...)

But it got me thinking that I would benefit from having something which 
would check for "bad" exit_codes and take further action.  Of course I'm 
not very good at procmail so I'm still learning there.