The unionization of workers at one Costco location may not have a significant immediate financial impact on the company as a whole. However, it could lead to increased labor costs in the future if the union engages in collective bargaining for higher wages or better benefits. It also raises the possibility of similar actions at other locations, which investors will be watching closely. The news is relevant as it directly involves Costco's workforce, but its importance is moderate given that it's currently isolated to a single location.