Spam, the question you asked, if it could be answered exactly would suggest that it is possible to behave in a way that would ensure you got the choice you wanted.
It doesn't work. You might aim for, say ME, and just fail. They may then NOT give you a restream and that is that, you're out.
Just do your best, go with the flow and ultimately keep your mouth shut. OK to express a preference once but once you are in the 'wrong' stream you must concentrate on what is and not what might have been.