Oh that reminds me of a funny story. I used to work for a company that sold various software and one month after their purchase, they'd get an email asking if they would like to review the product. If they ignored that, after another month they'd get one more email asking if they would like to review the product (after that they'd get no more emails).

Well I was going through and approving the reviews (just for stopping spam reviews), and I found a guy leaving a review explaining that he's very sorry but he hasn't had time to use the product as his wife has come down with a bad case of the shingles - I seem to remember he went into quite a lot of detail and obviously hadn't realised this review could have been made public.