Imagine the following scenario: the company is a service provider. Its service quality is going down lately. They send survey links to their customers a couple of days after the service is completed. It is now a problem because the reviews are bad, so it might hurt the company's image.
Is it legal not to send surveys to those customers that they know for sure that are going to give bad reviews? Or is it just morally questionable?
There is no requirement that a service company do customer surveys at all, or that it report the results. If they use customer surveys in advertising and the results are falsified or misleading, that might constitute false advertising, and be subject to government enforcement.
But if the report survey data as of a particular date, and mentions that date in the ad, that is probably not misleading enough to be unlawful, even if the company knows that later surveys show different results.
If the company just tosses all bad survey results and reports only the good ones, that is probably misleading. But they can report specific "customer testimonials" even if they are not typical, as long as they do not claim that they represent the average customer experience.
