Be able to set default for Weekly Summary email notification

Would like to be able to set a default on the Weekly Summary Email checkbox so that as new users are added, the desired default value would be assigned to those users in the Product --> users screen. Currently running into the problem of having a large number of users and adding new users all the time and wanting the default for the weekly summary email for these users to be off. There is concern about sending out too many email notifications across the user community. If a default could be set to off for new users, this would eliminate something they need to remember to do manually as new users are added.