Who is Mexican Officials from The Log from the Sea of Cortez and what is their importance?

Mexican Officials greet the group and review their papers in each of the port towns they visit. The officials can often be seen from the boat, lounging along the shoreline. Before going out to the boat, however, they must find their uniforms, clean themselves up, and get "official". Once on board, they examine paperwork, offer and smoke cigarettes, and sometimes join the men for a small drink. The party obtained impressive credentials from the Mexican embassy before leaving and havr no trouble anywhere in Mexico in spite of the war and the volatile state of politics in Mexico.