This is not entirely correct. They do allow some types of punctuation, and have done for a very long while. I haven't tested characters like #, @, & (etc) though, but periods and the like have worked.
Users are put at risk because Blizzard fails to adequately impose security. Tech savvy users can just use a stronger password, but the others are put at risk by what I can only call negligence.
Phishing, keyloggers and various social hacks are the real problem. Blizzard has always been very active in this regard with their constant and visible reminders that "Blizzard will NEVER ask for your password", but most users disregard even that.
I apologize if this is worded badly. I'm not feeling up to my usual ritual of rewording my post until I'm convinced it makes perfect sense to those who don't have magical insight into my mind.
Users who opt to (I'm not talking about forcing users to use capitalization here) to use capitalization for a more secure password are unaware that their efforts are in vain.
Also, it isn't only trivially more guessable. That's nonsense. If you're using a password list and you capitalize only the first letter of every password in that list, that list is still double the size of the first list.
EDIT: That doesn't even make sense, unless they're storing plain-text passwords.
The Java-based (J2ME) versions of the Battle.net Mobile Authenticator previously
available through this website have been discontinued.
http://eu.blizzard.com/en-gb/mobile/That company was namecheap, if I remember rightly.