I can see if their patent is truly infringed on that he could demand royalties, but it seems to me the whole idea of "treble damages" is based on having a product. If I create something, say a gadget that you install in your kitchen, and it warns you when food is burning, and then you create something similar and market it, too, if your gadget uses my patented ideas, I can say your sales have hurt my sales by X amount and demand three times X. For some reason, lawyers call this principle “treble damages” instead of triple. The idea is to have a really punitive system for patent infringement.
But, if I never actually make a single Burning Food Sniffer, and you do, how has your product hurt my nonexistent sales? I don't see it myself. It's like encouraging people to sit down and think of everything they might ever want to manufacture, patent it, and sit back and wait for someone with the money, time, and persistence to actual build the invention so that you can soak them for all their worth. That seems true in this instance as Discovery isn't asking to stop Amazon and Sony from selling eReaders, just to pay them big bucks for the privilege.
And of course, it remains to be seen whether their patent was, in fact, infringed upon, as there are many ways to remove the outer covering from a feline. And this particular feline was skinned 17 years ago, it's difficult to imagine the technology in the new eReaders existed when that happened. But we'll see.
Update: It seems Barnes & Noble may be considering marketing a wireless eReader to compete with Kindle. It's only a rumor at this point, but I wonder if Discovery will slap their names onto the same lawsuit if they do.