Currently in ArcMap, if there are layers from a connection with a saved password/version such as guest/welcome/default for read-only featureclasses and layers from a connection without a saved password/version for editable featureclasses... the read-only permissions override the blank connection.
In my example we have read-only basemap layers in an edit map with guest/welcome/default version saved in the map. When our water utility editors open the map they are to be prompted for their login/password/version for the editable layers.
When one of the layers with guest/welcome/default is at the top of the table of contents the connection information propagates to all of the layers in the map. So our editors don't get prompted for their login information and can't edit. Our workaround has been to make sure that no layer with saved login information is above editable layers in the table of contents...but I would like this to be a non-issue in ArcGIS 10. This was not an issue in previous ArcGIS versions.