You should secure the gimbal when transporting. PhantomHelp has a good list under Accessories/camera if you want something other than the DJI supplied lock.
I am very new to owning a quadcopter and the first thing I did was loosing the gimbal lock
I have been lucky so far, but of course I am not going to take any more chances there.
I am ordering the gimbal Lock from DJI ...
I was wondering if this type of lens cap / lock combo is a valid and possibly better alternative to use during transport (in the DJI backpack) http://www.ebay.com/itm/261909892138?rmvSB=true