How is osm protected from on purpose mistakes?

Somebody in a Greek forum asked how is the whole osm system protected from someone who registers to destroy the maps? What could I anawer?

Thank you

Everything is versioned, so a vandal could submit a change(s) that alters or deletes data but the working group could revert the change(s).

In many places local mappers watch for changes in their area and would quickly notice the issue. If they were unable to fix/repair the damage they would be sure to report the issue to the data working group.

For myself, I’ve setup a RSS feed with lat/lon bounding box around where I live and I get notified of every change that affects map data in my area. You can do the same, see:

… or try the newly introduced

zoom in to your target area, and wait the recent changesets from the past 7 days to be loaded.

To inspect a particular changeset, try the “achavi” link!