Your "logo" example is too contrived. What is more typical is to get a design for something like a form, that has made no consideration for user interaction (space for error messages, error icons, disabling/enabling buttons, etc.) This is where user interface programmers really stand apart from everyone else... Their designs actually work.
I'm sorry if it's contrived (I felt it somewhat related to the anecdote above); what I was trying to get at is whether designers have a point where they can't further deviate from their vision without compromising it, even if requested to by a co-designer or the client.
