For instance, all commercial A/B testing services (as far as I can tell) compute the 99%-Winsorized stats for their reports. This is partially due to several common cases that can mess up an average computation, especially between two halves: How many times has the developer testing account clicked on “Buy”? Obviously, those should not been the dataset in the first place, but when dealing with corporate clients, the commercial thing to do is to fix the problem and not confuse the client with the details, unless they dig in the documentation.