Google is hard at work bring many of their products together. It only makes sense tying Google+ into as many Google services as possible, making it easier for users to share content with their circles. It was just a week and half ago that Google integrated application installs into Google+, Google+ profiles have been integrated to YouTube, and now they are bringing your Google+ profile to your Google Play content reviews.
Currently the integration looks to be rolling out in phases. The G+ profile integration will hit both mobile & browser-based Google Play. You will be notified of the change and the integration will automatically happen (there is no option to opt out). Some will see this as being forced, but like any solution for any Google Services if you are not pleased with a change Google has implemented to their service simply do not use it. In this case, do not leave reviews if you're afraid of outing yourself.