"Poor technique"?

[depstein at att.net]

Robert Brenstein quoted Scott Raney:

"open
>inv" is poor technique in MC anyway (it's only there as a SuperCard
>compatibility feature), as is setting up fields in one stack from
>another directly.  Instead, do the init in a preOpenStack handler, and
>get the data in the dialog from a well known place (use the dialogData
>property if you don't already have such a place).
>   Regards,
>     Scott

Why is "setting up fields in one stack from another directly" a worse 
technique than writing data to a global property and having the preOpenStack 
handler transfer the data to that stack?  I can see that the latter might be 
convenient in some cases, but is there any important reason not to do the 
former?  Similarly:  is it in any way better to set custom properties of the 
second stack before opening it than to set the text of its fields before 
opening it?  

The ability to read and write to fields of unopened stacks is very powerful; 
Raney's remarks suggests there are some limits on how this should be used.  
Can anyone clarify this?

David Epstein