to a certain extent, I think it depends on a) how well they have been spun b) how similar they are to the original article, i.e. same paragraph, sentance structures etc...
People give too much credit to the big G, it is a machine not a human, therefore there are only going to be certain variables that it can adhere to. If you are smart with spinning then you should lie undetected. If you make an article that is in structure identical to the original and have changed few words, then you will see negatives on it eventually if not sooner rather than later.