People leave personal messages on a building under renovation, remembering the victims of a shooting on Sunday evening on Danforth, Ave. in Toronto on Monday, July 23, 2018. Arguing that the use of smart technology in gun manufacturing could have prevented a deadly mass shooting in Toronto's Greektown will take a proposed class action launched on behalf of the victims into uncharted legal territory, a lawyer for the families said Tuesday. THE CANADIAN PRESS/Mark Blinch