Midwest Moving Co. is a nonunion commercial moving and storage business. The International Brotherhood of Teamsters, Local 55, has been trying, without any success, to organize Midwest’s employees. Midwest signed a contract to relocate Morgan Stanley’s local office to an office building in downtown Chicago. The union learns of the upcoming job and notifies the building owner that it intends to picket at the building when Midwest employees are present there. The building owner informed the union that Midwest would be required to use the loading dock at the rear of the building, and would only have access to the loading dock after 6:00 P.M. and before 8:00 A.M. the next day. Shortly before 6:00 P.M, several union members began distributing handbills on the sidewalk in front of the building, and as the Midwest trucks approached, several other union members carrying picket signs began to walk back and forth in the alley near the loading dock at the rear of the building. The picketing was peaceful, but Midwest complained that the picketing made it difficult for the Midwest trucks to approach the loading dock. The building owner and Midwest both filed complaints about the picketing with the NLRB. Is the union picketing here primary or secondary? Why? Is the picketing in violation of Section 8(b)(4)? Explain.