> However, uppercase is perfectly valid to RFC822 and should be allowed.
> It really is the spam software that needs to be fixed.
> 
> Please forgive me if I am giving out any incorrect information, this
> is how I remember it.

You are 100% correct, uppercase is perfectly valid per RFC 2822. 

My first thought also was it's the spam software that needs to be 
fixed, not LISTSERV, because it ain't broke.