I had to move a lake in Schwandt (Mecklemburg, Germany) which had originally been created by a different user. This lake just didn't fit into the bounds of the surrounding footpath I had surveyed.

I always feel uneasy changing stuff of other people, they might had a reason to do it that way that I am not able to grasp. This time I was a little pressed and went on simply because the original creator had stated landsat as source, which I could cross-check. As most of the other things this particular user had mapped in this area perfectly agreed with the landsat image I could get, I assumed that I had the image's bearings correct, and that somehow the image had changed in between, or the original creator had gotten something wrong.

In the name of cooperation I should inform the original creator. This could easily be done through the user-pages (I simply failed to find the correct one this time.)

Actually I don't know if there are any guidelines for such cases, and I would strictly vote against setting up such a thing for avoiding rule-discussions like they are familiar from the wikipedia community. But good behaviour should be to inform the other creators of a changed shape.

And by the way, if somebody comes through that area, I had to left some roads uncharted. These road-stubs look just silly and I'd like to improve on that. So, could anybody lay a track there? (Rare opportunity to introduce some new roads to the increasingly complete OSM-Map.)