On the other hand, if they told you in advance that you'd have to delete the review copy, then that is the end of the discussion. (law.stackexchange.com)
I suspect that they are deleting reviews posted by anyone who hasn't been on amazon in x amount of days. (killzoneblog.com)
They won't delete all reviews, but if they violate their terms of service, they are usually really good about deleting them. (trainingauthors.com)