Answer
The Disconnect command should only be used in a transitory manner. Do not use the command to:
1. Maintain geographically coincident junctions/edges that you don't want to be connected to the surrounding network features. There are operations in the geodatabase that may reconnect coincident features.
2. Disconnect network features for the purpose of Tracing. To disable features for network tracing use a network weight or toggle the Enabled value of the feature.
Be aware that disconnected network features cannot be discovered by simply viewing the data. Disconnected features are still coincident with surrounding features and can appear to be connected. The only way to identify if a feature is disconnected from surrounding features is to:
1. Perform a Find Connected Trace
2. Pick up and move the feature
Persisting disconnected network features can lead to incorrect Trace results. When disconnected, the feature is not affected by edits to surrounding features.