If this occurs, the aircraft can still fly, land, and maneuver with the wings in any position. Asymmetric extension is prevented by the design more so than with some conventional flaps. So the Gevers telescopic design is simple and safe. Weight and drag are the obstacles to achieving high performance. The wing drag is the sum of two components, induced drag and parasite drag.
Induced drag is due to lift and parasite drag is mainly due to surface friction.
Increasing the size of a wing increases its parasite drag. For low speeds the majority of the drag is induced drag and at high speeds it is parasite drag. So the large wing that is beneficial for low stall speeds is detrimental at the high cruise speeds. Ideally, one would want to remove the extra wing area used at low speeds in order to reduce drag during cruise and increase speed and efficiency. This is exactly what is done with the telescopic wing.