LISTSERV also catches signoff requests sent to the list. The problem is
that users are getting increasingly creative at making up syntaxes that
don't exist and are thus not caught. Another problem is the incredible
amount of new users with signature files of 15-20 lines. LISTSERV only
looks for commands in short messages, on the assumption that people are
unlikely to send 20 subscription requests in a single file. It's all a
tradeoff between catching the bad commands, and preventing legitimate
messages from being posted. I have increased the "small message"
threshold for the next version, and also added a couple of the most
popular subscribe commands that don't actually exist :-)
Eric