When do Validators not work?

Please correct me if I am wrong, or agree with me if I am right.
1.  Validator.Enabled == false;
2.  Before Page.Validate(groupName) is called, BaseValidator.Validate() is called.
3.  If a Validator is not being displayed, such as being in an non active View of a MultiView.  I even wrote a Custom Validator that was in View.  It checked if Validator.IsValid and it returned true when it wasn't. 
Is there any way to get around number 3?
 
...