Yes, an on-going opt-out list is maintained. In order to keep this list updated we work with the cities where we are delivering to incorporate any opt-out addresses they have on file.
In addition, if a resident notifies us they do not wish to have a door hanger or sample delivered we add their address to our cumulative list. All program data and mapping is run through this list to ensure homes that do not wish to be delivered to don't to ensure compliance.