One of the shortcomings of the Hipster PDA is the vulnerability of your data, if you lose your Hipster (or parts thereof). Even if your handwriting is terrible, people still might be able to decipher your next actioned groceries or business ideas.
Handywrite is a beautiful (and open sourced) handwriting system which will give you pretty good protection of your data from spying eyes. You only write what you hear using the simplest possible strokes. Handywrite even offers data compression, if you apply the built-in abbreviating principles.