text: >Remember that things may have changed since the photographs were taken; we are trying to map what is there now and not when the photographs were taken.
  https://wiki.openstreetmap.org/wiki/Beginners_Guide_1.1.2
  
  >Things change. Imagery gets old. Road layouts change. Buildings get knocked down and rebuilt in different places. Imagery can be many years old. Armchair mapping involves blindly copying this information but in an area where locals have contributed, you should be very careful about this. Look out for tell-tale signs. If the whole area has building outlines drawn in, and you see just one missing, or one drawn in completely the wrong shape, don't just "fix" it. Alarm bells should be ringing.
  https://wiki.openstreetmap.org/wiki/Armchair_mapping