Many "smart" officials learn early in their careers to pack extra "stuff" (shirts, whistles, flags, even pants, etc) in their equipment bags to cover for their crew mates who may have a brain fart and forget something. It can cause some (usually humerus) ill-fitting situations, but is better than having an odd man out, who is most often subject to post-game meeting (buying) consequences.
However, in the BIG picture, it's really not going to affect the game, or matter very much to anyone other than other officials, on the field, or those watching from afar, or on film long after everyone has gone home.