Dear #Drupal diary: Today we wanted to do a node_save programatically that populates an extra field in case it's empty.
But since revisions were enabled and we were doing this in the node_load hook there was a problem. The node_save created a new revision of the node with the uid of the currently logged in user.
Suddenly the content of the `Almighty USER 1` was falling to the hands of the 'enemy' (some other user who is currently logged in). But then after some research found out that this will be resolved in Drupal 8.