who was to blame?

Romeo and Juliet

Where would the audience perceive the blame to lie for the tragedy of Romeo and Juliet?

As with many things it is difficult to lay the blame on one specific occurrence as even the slightest mishap, especially in this story, can mount to something far worse than ever expected. The question I am trying to answer is where the audience would perceive the blame to lie and personally I feel the answer to that question lies greatly with who the audience actually is.
A modern day audience compared to an Elizabethan one would have vastly different opinions, as would a teenager and his or her parents. Nevertheless, right from the first page in the book it becomes apparent that this story isn't going to be black and white. The two families' 'ancient grudge' is the first insight of many more under-lying occurrences to come. Each one having a small yet significant influence on the end result of the story.
A sensible approach to this question would be to firstly try and n...