I remember a customer once who wanted to PROVE the Wi-Fi was working properly by having hundreds of people all run an Internet Throughput Test AT.THE.SAME.TIME!
Think for just a minute on that... would you trust the results? Is it really testing the Wi-Fi, or the RF capacity, or the laws of physics, or your ISP's bandwidth?
How do you answer your clients/customers when they want to use an Internet Throughput Test as 'proof' the Wi-Fi is working properly?