Conversation so far:
What is the marching technique?
Given that instrument-wielding members most often face toward the audience (for maximum sound projection), marching technique must not affect the rigidity of members' upper torsos.
How rigid is their upper torso supposed to be?
members of the battery, due to the nature of their equipment, must keep their entire bodies facing forward at all times.
What is another factor of their technique?
Horn players may twist their lower bodies in their direction of movement, but members of the battery, due to the nature of their equipment.
What are members of the battery supposed to do?
must keep their entire bodies facing forward at all times.
Why can horn players twist their bodies?
This has led to the invention of the "crab walk" or oblique, where the legs cross over one another to facilitate sideways motion.

Question: Does the whole group do the crab walk?
Self-contained rewrite: Does the whole Drum and bugle corps group do the crab walk?