I'm not sure why they would attempt this. If they think they're going to get DMCA protection out of it, Lexmark already lost a case that seems to be this exactly:
IANAL but the Lexmark case doesn't seem like it necessarily says the DMCA doesn't apply to physical products, just that it doesn't apply in the way that Lexmark implemented it. Also isn't part of the case still pending decision of the Supreme Court?
Lexmark Int'l v. Static Control Components http://en.wikipedia.org/wiki/Lexmark_Int'l_v._Static_Control...
All they can do is make it harder for competitors to make compatible cups, but that sounds like a fool's errand.