Rules of a complex element SS4

I am just looking for some guidance and information on rules.  Below is a screen shot of the rules that appear when selecting a complex element and our labeled as follows:

1.  Lock - Deactivate Rule

2.  Unlock - Activate Referencing Rules

3.  Lock - Deactivate Referencing Rules

4.  Remove Rule

I was wondering what these do exactly and how other people utilize these in their modeling?