Mobilization of volunteer mappers is a serious task that requires interpersonal skill and motivation. And when these volunteer mappers are mobilized, another issue to deal with is effective trainings to ensure the mappers actually map accurately, it is not solely about speed and quantity of data contributed. In recent times, most volunteer mappers in openstreetmap, especially the new volunteers, get excited and pumped up when mapping various HOT tasks and sometimes when such mappers are engaged in a mapping contest, say a mapathon, they may not put into consideration the accuracy of their mapping, if not properly guided. This paper, therefore, highlights the relevance of mobilizing humanitarian mappers, training humanitarian mappers, following up mappers activities as well as technical mapping accuracy in OSM mapping, to ensure mappers are not discouraged or demoralized when such issues arises. Examples are drawn from recent OSM community complaint about mapping accuracy by some volunteer humanitarian mappers. Conclusively, the paper highlights best ways to address issues of mapping accuracy in OpenStreetMap.