A wedding dress is built to be worn once and admired forever after, which means beading, lace, and delicate seams need support they were never designed to hold up under during a move. Padding the shape from the inside out prevents most damage.
Pro tip: If the dress has significant beading or a train, consider a professional preservation box designed specifically for wedding gowns; it is a one-time cost that protects the dress for decades.
Watch out: Sealed plastic bags trap moisture against fabric, which can cause yellowing or mold over time even from a single humid move.