In order to get timely feedback from stakeholders we have built a fixed duration into V|Vs of five days. As soon as a V|V is published, an email invite is sent out to all specified invitees. In that email they are informed that the V|V has started and when it will expire. When people browse a list of V|V in the Visual Vocal mobile VR application, they will also be informed of how much time remains in the feedback period for the V|V.
After a V|V expires, people with appropriate permissions can still view the V|V content -- they just will not be able to submit feedback.