I've actually seen a few projects that use this method over the past few years, and I think you're overestimating the challenge. Once the servers know the fing

I've actually seen a few projects that use this method over the past few years, and I think you're overestimating the challenge. Once the servers know the fingerprint for a device, they can recognize that fingerprint in multiple homes. The device doesn't have to get everything perfectly correct right away, but it will recognize a fridge/freezer vs a dishwasher vs a television. A combination of use times, power load etc etc. I'm not saying it's easy, but enough people have done or attempted to do it using the same method that I don't think it is probably as unreliable as you suspect.