Abstract: A retail establishment advertising system and method are disclosed. They allow a display of special content to interrupt a display of ongoing content on one or more display units. Ongoing content, such as advertisements, news, entertainment, or other relevant information, is provided on the display units until an urgent or security-related alert is required, and display of override content becomes necessary. Special content can include information relevant to specially discounted items or to security alert messages pertaining to, for example, security threats such as accidents, major delays, fire, missing children, terrorist activity, or other content deemed adequately pertinent to warrant interrupting the display of ongoing content.