[Exim] Rejecting bounce messages with multiple recipients

Hi

I'm thinking of enabling :-

    deny    senders      =    :
        condition  =  ${if ! eq {$recipients_count} {1} {yes}{no}}
        message    =  Invalid use of null sender

to block mails with "<>" as the sender address *and* multiple
recipients. The reason for this being the occasional mail virus/worm
that uses this sender address.

I'm aware that "<>" is a valid sender address and used for bounces, but
is there any valid use of it with multiple recipients ? And is the ACL
snippet above reasonably sane ?

In other word, am I about to make yet another dumb move ?
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Mike Meredith, Senior Informatics Officer   /~\ The ASCII
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