A restraint system for temporarily restraining a generally rectangular panel in an opening of an outdoor structure having a pair of longitudinally extending side portions, a base portion connected to each of the pair of longitudinally extending side portions at respective proximal ends of each of the pair of longitudinally extending generally parallel, inwardly inclined side portions, protruding members arranged along a bottom surface of the base portion for frictionally engaging a side portion of an opening of an outdoor structure during an operational use of the restraint system, and a tab portion configured to allow a user to grab and pull the restraint system out of the opening. The pair of longitudinally extending side portions and the base portion form a generally u-shaped configuration with a gap therebetween adapted for receiving a side portion of a generally rectangular panel.