In WC, change the BlackList method for better security concerns.
The current method requires the user to open or preview an email, where some threats take place at time of open or preview.
Rather, demonstrate a right-click or menu button option that will display only the list of email accounts within the message to toggle the choice to BlackList any and all accounts within that one message in one sweep.
We follow a policy to never preview E-mail, and coupled with viewing Email's full contact information, we prevent many of the issues that threaten payload type threats. (too bad I can't add a screen capture of what I mean right here.)