I think it's pretty clear that they will use some sort of signing process to validate swfs, and in some respects it'll be pretty similar to DRM.
In the original announcement, they say, "When the premium features licensing terms go into effect, unlicensed content will continue to run but will no longer have access to the premium features tier". Which implies that somewhere in the player they're planning to have a if(date() < August 12, 2012 || signed()) bit of logic.
In the original announcement, they say, "When the premium features licensing terms go into effect, unlicensed content will continue to run but will no longer have access to the premium features tier". Which implies that somewhere in the player they're planning to have a if(date() < August 12, 2012 || signed()) bit of logic.