I hold a licence that allows me to transmit on pretty much whatever frequency I like with as much power as I like, wherever I like.

Someone has to test the transmitter before you hand it off to the customer.

Also, I'm in the UK, where it's hard enough to get the regulatory authorities to do anything about people causing interferenced to licensed chunks of band. You can wipe out the whole of 2.4GHz if you like, you literally could not pay them to take an interest.

Edit: also you have probably done the same a couple of times today too.