>Hiya Ed ---
>
>>
>>IMO, object shouldn't access directly property/methods of objects of the same tier, but have to use property/methods of objects of upper tier to do this job.
>
>Why the difference? I mean, as I undertand COM and CORBA, the whole idea of following standards is that they should apply logically, not physically?
>
>This is interesting...Please enlighten?

It's just my understanding. Upper-level object is always here, while lower-level object can disappaer/reappear, so it's up to upper-level to make analysis (at least checking is this object exists or not) and then make an action upon this object.