What riding skills for general (unloaded) mountain biking also apply to riding with panniers, rackless luggage systems, or trailers, and which skills have to be modified or abandoned? Let's take bunny hops as an example: I'm guessing that a bunny hop is:
a. moderately effective with a rackless cargo system or backpack
b. largely ineffective with panniers
c. impossible with a trailer

How about other riding skills for dealing with obstacles, hills, and various trail surfaces? What skills work and what don't? Are there any skills that only apply to loaded riding that you don't use at all when riding unloaded?