meh, I guess i must be stupid to not care about this because I am so lucky to have stable internet.
Anyways, i remember the same outcry happening when it was announced that sc2 would require constant internet access as well, so blizzard added the "play as guest" feature so that you can play offline (and that requires you to have logged in once with your copy first). And they'll most likely do the same thing with d3. I wouldn't spend my twilight hours worrying over this:)