Of course, if you join a manually maintained list, you
> don't get off until the list maintainer lets you off.
 
Another reason for not 'letting' the users unsubscribe is their own
frustration factor.  We have a number of lists with different topics.  The
user decides they want off and they send the command with the wrong list
name.  It doesn't work.  They get frustrated.  They try something else.
Still doesn't work.  No need for our users to have to understand our
structure and naming conventions (which change anyway).  By the time they
write to us, they are pretty mad.  Easier for them to just write to us
first.  We have no reason to keep any user on a list that they want off
of.
>
> Another way to at least make it difficult for someone to leave a list
> is to subscribe them under an address that gets the mail to them, but
> is not the one their mail system puts in their From address.  Happens
> all the time by accident as mail systems change the addresses they use.
> I'm not recommending that people do this on purpose.
 
We have seen this problem also.  There are a lot of confusing mail systems
out there.  This problem also comes up with my 'volunteer' list.
 
Sandy Barnes