While I read such anecdotes, I cannot rely much on them for research. Instead, what we did for our paper was to collect thousands of filtered reviews, and check

While I read such anecdotes, I cannot rely much on them for research. Instead, what we did for our paper was to collect thousands of filtered reviews, and check their characteristics against reviews Yelp publishes. We find that filtered reviews are shorter, more likely to be from one-time reviewers, more likely to be extreme (1- or 5-stars), and so on. I realize this does not constitute absolute proof but at least it's evidence based on data. Check the paper for more stats. Beyond that, and as a counter-anecdote, I have read hundreds (if not thousands!) of filtered reviews over the past year and in my experience they are more likely to be fake. Furthermore, one implication of challenging our assumption is that you are suggesting consumers would be better off reading, and basing their decisions on filtered reviews since -- by your assumption -- they are more likely to be genuine. As I said, I cannot offer proof, but given what I have seen I believe the filter to be more likely to catch a fake review than a real review.