Remember that if you cut and paste SCANed addresses that some
folks subscription options will be either nomail, digest, index,
short822, ack, repro, etc.
 
UNSUBing / SUBing via simple SCAN is not going to "cut it" ;-)
 
Maybe you should consider a DNS RR of MX along with appropriate
SENDMAIL (?) support?
 
/Pete Weiss at Penn State