Here is a test

Go to the initial pool of  juries from which all the juries for cases in that court get selected. Then start taking random sampling and ask them if they would have voted the same way the juries in this case did. Then based on that calculate the probability that real random selection of six juries would lead to none of them would vote guilty or remains neutral.

Anyone can do similar sampling by looking at opinions of different people. The general opinions I saw does not support that there is good chance for a six persons all of them would vote not guilty in that case with random selection.

Another reason for sequestering the jury and the defense's opining joke of "Zimmerman who?  Good you are on the jury" could be a way to preemptively answer the results of such sampling by suggesting that public opinions are influenced by the media and therefore cant be counted on which is a joke.

Whether to preemptively counteract a general opinion and/or just to hide more a connection and/or preparation of the jury for the defendant,the exaggeration level the defense took with that joke was clear. That exaggeration or unnecessary addition that seems for defensive purpose can be noticed through two paths, the action itself and the
kind of action taken. The defense could have stated that the jury did not have a relationship with the defendant, and that is a reasonable statement on its face, but still one may wonder what made him emphasize that thing. But the defense did not limit himself to that level to achieve his purpose but took the exaggeration level of the joke mentioned above.Who would answer "Zimmerman who" with a case with such publicity? Assuming you could get a jury who would answer "Zimmerman who" what are the chances that you achieved that without sacrificing other things that may not be easily found in people living in a closed box suggested by such answer? Moreover, the general public opinion was clearly against the defendant so why would the prosecutor agree with you on such sacrifices unless he is on your side and part of the plan?

Also, I am not sure if his statement of  "Good you are on the jury" or something similar to that should be understood as an admission that that condition existed in the juries but if it was then for what purpose a lawyer would make such a voluntary admission other than to defend against a connection to the jury and/or prepare for a result he knew the jury was prepared to deliver?