It is not helpful to copy streetnames from OS Locator for places you have never visited.
It is not helpful to change correct streetnames, which have been properly surveyed.
It is not helpful to copy all of the blatant errors from OS Locator into Openstreetmap.
It may be increasing the numbers for 'completeness', but it is not improving the map. It makes it much harder to find actual errors, or places that need surveying.
Plus it is discouraging people from actually going out and surveying their area.