The review guidelines seem to take aim at those who leave bad reviews or good reviews without really using the company's services. Let me quote the new guidelines:
Google will rarely remove reviews but now they can if:
We want to provide a clean and positive user experience for all users. We may remove reviews that contain or link to unlawful content, or content that violates our Google Places content policy. We may also remove reviews that include plagiarism or are copied from other sites.
Advertising and spam
Nobody likes spam and it can only make its author look bad. Don’t use reviews for advertising or post the same or similar reviews across multiple places. Obviously, don’t post fake reviews intended to boost or lower ratings.
Reviews should describe your personal, first hand experience with a specific place. Please do not post reviews based on someone else’s experience, or that are not about the specific place you are reviewing. Reviews are not a forum for personal attacks, rants or crusades. Please also do not use reviews to report incorrect information about a place -- use the Report a problem link for that place instead.
Conflict of interest
Reviews are only valuable when they are honest and unbiased. Even if well-intentioned, a conflict of interest can undermine the trust in a review. In addition, we do not accept reviews written for money or other incentives. Please also do not post reviews on behalf of others or misrepresent your identity or affiliation with the place you are reviewing.
How do you report a review to be removed by Google? The process for reporting a review that violates Google's policies hasn’t changed. You can still report a review using the "Flag as inappropriate" link found next to each review submitted through Google Maps.
Forum discussion at Google Maps Help.