In an email update from DJI today, DJI indicates:

Propeller Locks

The Inspire 1’s propellers may come off during flight if they are not correctly hand tightened and environmental factors (including sand, heavy dust, or high winds) cause the motors slow down suddenly. To prevent this, DJI is offering free Propeller Locks to all Inspire 1 customers.

If you ordered your Inspire 1 from the DJI Online Store, they will automatically be shipped to you. If you purchased your Inspire 1 at an authorized DJI dealer, you can collect them there. These Propeller Locks will become available next week, and DJI recommends that you do not attempt flying your Inspire 1 before receiving and attaching the Propeller Locks.

Any insight on how prop locks work?

i think they lock the props...like a wingnut of somesort