[eluser]xwero[/eluser]
Yes you have to add the flag everywhere where an email is generated in the system. But this adds a whole new feature to the system once the full ACL functionality kicks in, which is the base of the problem IMO.
If an added module that has nothing to do with the system uses the email class, it will use the overwritten method too. I think method overwriting of the core libraries should be kept to a minimum.
if you are dead set on extending the email class do it with a new method then the link between the system an the email method will be more visible.
Maybe i'm seeing it too big and is it not needed to think about future changes and additions.