Unfortunately all they have to do is unsub and resub to defeat this unless
you have Default-Options= NOPOST in the header.

Why not simply moderate the list for a while?

On Wed, 23 Dec 1998 20:59:15 -0800 Michael S. Johnson said:
>On Wed, 23 Dec 1998, Lance A. Brown wrote:
>
>> I [...] am considering stopping the flow of messages for a short period
>
>How about this:
>
>        quiet set listname NOPOST for *@*
>
>Then, when you're ready for posting to resume:
>
>        quiet set listname POST for *@*
>
>
>Hope this helps,
>
>- Michael