60 Billion Habitable Planets in the Milky Way Alone?

http://www.universetoday.com/103379/60-billion-habitable-planets-in-the-milky-way-alone-astronomers-say-yes/

I posted a comment questioning the viability of tidally locked worlds, since I think evaporation and precipitation would eventually cause the light side to lose all its water, which would precipitate out into the dark side. I've received a couple of responses, but I think one is false and the other irrelevant.