[thelist] how do you manage/respond?

[Bob Meetin]

* Every time the customer comes up with a new requirement, you simply 
work out what it would cost to implement (in terms of cost *and* 
schedule (and risk to anything else you're doing)), and check that 
they're happy to proceed with it. *

==>>

This sounds good in concept and is reasonably doable if you coded the 
application but when you're implementing an open source application and 
have to dig/research through unfamiliar code the simplest changes may 
take many hours if they are even doable. 

If as in this particular case you are assigned to work with someone 
whose job is to populate the cart (not the financially responsible 
party) who does not care nor understand the requirement process, all 
that you will hear is, "Why can't you do this? This program is 
inadequate, is dumb, you baffoon!"

What I am looking for is the business and perhaps politically correct 
way of managing this type of situation moving forward.