I receive a lot of review books, but I have never once told lies about the book just because I got a free copy of it. However, some authors seem to feel that if they send you a copy of their book for free, you should give it a positive review.
Do you think reviewers are obligated to put up a good review of a book, even if they don’t like it? Have we come to a point where reviewers *need* to put up disclaimers to (hopefully) save themselves from being harassed by unhappy authors who get negative reviews?
I believe that if you are sending your book out to be reviewed, you need to understand that there are going to be people out there that aren't going to like it. Not everybody thinks like you, and not everybody is the same as everybody else.
I think that as reviewers we should give an honest review, but if we don't like it we should also temper it (if possible) with at least something positive about the book.
I have been known in the past to not review a book if I didn't like it, but I've changed that now because I want to let my friends know whether I liked a book or not.