one of the documented procedures in this installation of the ACS
bozo_filter_blurb   sender_id
What it does:
A blurb to append to any spam message, letting the user avoid future emails from this specific sender
Defined in: /web/philip/tcl/user-group-defs.tcl

Source code:

    return "

To stop receiving any future email from this specific sender :
click <a href=[ad_url]/user-user-bozo-filter?[export_url_vars sender_id ]>here</a>"