The final remedy of the servant, then, was flight. From the beginning of indented servitude, the servants invariably deserted their master's service. While in all cases they did not run away on account of abuses, the practice brought on abuses and other incidents which, during the first part of servitude, became more and more intolerable. The number of runaways increased as the servants continued coming in. It was comparatively easy for them to escape to the more northern colonies, since the country about them was convenient for hiding and clandestine traveling; and the fugitives themselves, on account of having no physical characteristics distinguishable from those of the other colonists, could not easily be identified.[33] Thus North Carolina became popularly known as the "Refuge of Runaways" and that colony, Maryland, and the Dutch plantations were to fugitive servants what Massachusetts, Ohio, and Canada were later to runaway slaves.[34] The "under-ground railroad," too, had a forerunner in the early period of indentured servitude.[35] Methods of dealing with the runaways necessarily grew more strict, and precautions similar to those of slavery inevitably appeared. "Unlawful assembling," "plotting," and tentative insurrections became a source of apprehension.[36] Then came methods of pursuit, return, and punishment of the fugitives. Sometimes the master made the pursuit; at other times the sheriff and his posse did it; and often the constable with a search warrant went in quest of the fugitive. Everyone who traveled was required to have a pass or a certificate of freedom to show his status;[37] and this no doubt afforded the servants a means of using forgery to facilitate their escape to freedom.[38] Again, whenever it was possible, advertisements for runaways were put in the newspapers.[39] During this time, too, there were enacted colonial statutes providing for the return of fugitives by one colony to the other. Colonial governments often accused each other of unduly holding and protecting the runaways.[40]