although wire does add strength for extracting, this is not the main reason for wiring foundation.
properly done (no matter how you do it), the foundation should be attached firmly to the top bar (either with a wedge, or by attaching with melted wax), _and_ embedded with horizontal wires. this keeps the foundation from moving around and sagging under the weight and heat of the cluster.
the frames we got from don were done with an "X" of fishing line on either side of the foundation, with no embedding, and not attached to the top bar. the resulting comb was drawn poorly (especially at the corners).