Why doesn't model.setX() set model.belongsToXInstance?

[el_chief]

If a parent model is read successfully using either nested or remote loading then the child.ParentBelongsToInstance is set to the parent.

I am just curious as to why child.ParentBelongsToInstance is not set when calling child.setParent(parent)

Example:

http://jsfiddle.net/el_chief/XgnZP/6/

T (http://jsfiddle.net/el_chief/XgnZP/6/)hanks