First, let me assert this: There is NO such thing as “purity and sanctity” of a customer review of a business. Of ANY business, dealership or not. Why?
For any review "collector" (Google, etc.), trying to police reviews while thinking otherwise is Pollyannaish and is really an enormous “plate of spaghetti” (whether the reviews were performed on the business’ property or off)—because either, or both, the business and the customer may have agendas that bear little on the actual experience and more on their personal and/or business reasons. And that’s assuming the review came from a real customer—as both businesses and individuals can “game” any system of reviews, and they will. So, again, whether the reviews are done on or off property of the business does not change that.
And gaming is hard to fairly detect, even if you start by looking at a pattern of reviews done by a single individual, or reviews done once by an email that is never used again, etc. None of that will ever be fair—because, for example with Google Places, customers may or may not use Google as their primary email, they may not review often, etc. And seeing a review IP a thousand miles from a reviewed restaurant may just indicate a review after travel. And so on. What makes a lot more sense is looking for patterns of abuse that have to do with relevance of review content. And even that can be misleading.
As to IP monitoring, watching a business IP for review creation on-property is also unfair to both the customer and the business. Shouldn’t a customer on the business’ guest wireless be able to review that business? Should the business be forced to purchase tablets on the local cell network just to avoid being “detected” while taking REAL reviews from real customers?
And the whole idea that reviews that are asked for are somehow invalid is ridiculous: It’s long-known before the Internet that happy people don’t write letters and unhappy people DO. Modern online reviews are the same way; human psychology hasn’t been so altered on this point by the Internet as to make any difference in the outcome. Businesses have a right to ask happy customers to share their experiences because the business MADE THE EFFORT TO PROVIDE THAT EXPERIENCE. More so, the business has a responsibility to future customers to provide the full spectrum of their experiences.
Finally, understand that “gaming for profit” will happen in any review system. Customers have in the past threatened bad reviews (and will again) in order to get their way (or even gain financially) when they should NOT be allowed to do so; businesses will also be approached by 3rd parties who promise “great reviews” from shill customers in return for $. And combos of all that and more will happen. NO MATTER WHAT IS DONE. And the more policing that is done, the more valid reviews will be discounted. And lost.
The best path is to remain as neutral as possible and allow the market to do what it will wherever that is possible—and so reviews taken at a business are valid, but maybe reviews of a business that are always 5 star might need a look. However, the real push should be to educate shoppers on what to look for in business reviews so that they can police validity themselves.
Because customers started reviews of some kind way back in the annals of time. And they should be able to continue that wherever they want, unfettered, but strongly educated.