I have an idea on how to break the motivation barrier that threatens to leave people without converters to lose all access to television.
A voluntary agreement among TV stations to end NTSC COLOR transmission, on May 1st, with only monochrome transmissions through June 12.
The loss of color would provide, to many, a solid reason to get the boxes hooked up, it would produce a constant reminder that conversion is needed, and would serve as a constant "soft test" to see which sets are ready. Those objecting to the change wouldn't be able to plead that it would cause the loss of emergency/security communications to anyone.
Slogan: "May 1st is MAY DAY for analog TV!"