Two preconditions have to be fulfilled for observation monitoring to be carried out for the observations of a specific feature. First, observation monitoring must not be globally disabled (see global setting Miscellaneous: Disable observation monitoring. Secondly a each feature whose observations shall be spied must be marked as being spied. Newly created features are marked as being spied by default.

An observation monitoring definition defined for a feature or a group of features will only be used if these two conditions are fulfilled.