LISTSERV tolerates warnings for mail posted to a list. After all, human
beings are going to read it, and they have the option of using their
brains to figure out what was meant. LISTSERV does not, however, tolerate
warnings for messages containing commands that have to be executed. In
this case it would probably have worked out ok, in other cases it could
have led to incorrect results, possibly a loop, etc.
Eric