Oh, it seems that this is changing in 1.8 so that no blocks can be broken even with the correct tools.
Yea they change in 1.8 as well. You have to give a tool a NBT tag for it to work in adventure mode.
Ooh, interesting. Do we support NBT tags?
We support nubby tags, just not those specific ones yet. Nubby tags are stored during operation generally in cItem (like fireworks and enchantments).