The pass/tickets will have color coding that will change as the month goes moves along.I wasn't sure what this meant at first, but apparently the "ticket" will feature an animation with colors that change based on the day. The conductors will be informed each day of what the expected colors for the day are. That also explains why the conductors would need smartphones, since that's the vehicle used to send the validation information to the conductors. They wouldn't have to use them to validate every ticket, though they could validate individual tickets if they needed to.
Here's an example of what a generated "ticket" could look like:
So the good (and expected) news is that fraud will be much harder to accomplish. I still think it's not impossible, since colors change on a per-day basis and the nature of smartphones allows easy sharing of such data, but the level of effort required would move it to the "not worth it" category.
I also looked a little more for the Charlie Card issue, and the press releases state that the pass can be "linked" to Charlie Cards, so I think it means that I could buy my pass in the app and use the pass for bus/subway via my linked Charlie Card. This isn't explicitly stated anywhere I could find in a couple minutes of searching, so I could be guessing wrong. Of course, all of this means nothing if you don't have a smartphone.