Only way I know is to munge the address of the delivery template.  Eother cange the path or the filname to something that doesn't exist, and it won't be sent.  I do it all the time - delivery receipts are no good.

I could have sworn there was an option to suppress return receipts and that I was already doing that.  But for the life of me, I cannot find that option in the mercury config screens.  I'm on Mercury 4.7.2.

The reason I bring this up is the Mercury content filters moved a message into my spam queue and then Mercury gleefully confirmed receipt of the message to the spammer.  I would prefer not to send any receipts, but particularly these.

Thanks!