The MSC's legal advisors have really gotten their attention about this, long ago. . The client must have all employees sign an agreement to be audio recorded as a condition of employment. Never had a problem. Nor have any of the many, many shoppers that I have met at IMSC conferences, online, and otherwise, over my 15 years of doing audio recorded shops.
Based in MD, near DC
Shopping from the Carolinas to New York
Have video cam; will travel
Poor customer service? Don't get mad; get video.