A laser engraver's gantry moves fast and light, but its optics, mirrors, lenses, and on some models a glass laser tube, are the parts that cannot take a shock. Securing the carriage and capping the tube protect the two things that are expensive to replace.
Pro tip: Photograph the mirror alignment angles before removing them, since re-aligning laser optics from scratch is fiddly and time-consuming.
Watch out: Never move a laser engraver with the lens or mirrors left in their working position unprotected; a small shock can chip an optic that costs far more to replace than the packing job takes in time.