Blocking VPNs might be a bit controversial - there are legitimate uses for them beyond trying to circumvent tethering blocks, and it would probably open the discussion over whether the network operators should be engaging in massive DPI to enforce their arbitrary terms and conditions.

e.g. some companies like my former employer need you to use a VPN to do anything except basic email

I know, but I'm simply saying that further problems may be caused down the line if people start cheating, giving examples like capping unlimited data or blocking VPNs, making VPN use part of the tethering allowance or putting a quota on it etc...

Ultimately this whole situation is mainly because of a minority, that's my point, abuse it = lose it for everyone, especially people posting it on forums and encouraging other users to cheat too.

What is "cheating" though?

I listen to tune in radio a lot, probably 10-15gig a month. Sometimes I tether to do it, sometimes I don't.

I'd 'prefer' to tether to do it, but if not, it isn't reducing my usage.

If I have to cast my screen to watch say the football, this does affect me, as I don't know if tune in will still run.

I bought a hudl on the back of their offer, I wouldn't have bought the bloatware laden thing otherwise, and I'll be damned if I don't 'try things' to retain what service I have now (2 meg down on a good day).

Cheating = breaching the agreement you signed up to when you took the contract out.

He hasn't done any breaching as far as I can see.

100% Agree. One Plan customers are not to be blamed for doing what the network allowed as part of their contract. The network has to be responsible for allowing users to consume more than they could provide. The sympathy has to be with those who bought a deal that is now being changed with no apology and no explanation. It's more than shoddy and the best that can be said is that a minimum contract obligation has been honoured by the provider but that is a very minimum requirement and does nothing to encourage loyalty and suggests the network has been very short sighted about how they have marketed the tariff.

I didn't say they had, I was clarifying what I meant by cheating.. i,e the people using apps to try and tether outside of the tethering allowance.

Does bring up a good question about "casting" your screen though. Granted most apps that support Airplay and Google Cast just send the video / audio URL to the target device and it is that device that then pulls the stream from the wifi network that is connected to. However where someone is "casting" their screen to that device, then that data will be through the mobile and presumably Three will be unable to tell that the data isn't really being "used" on the phone.

Casting works by devices on a WiFi network communicating. A phone or tablet on the same WiFi network as a smart TV simply sends URL info to the router that is fed to the display device on the same network. You can switch off the mobile or the tablet once a connection has been established and the stream continues proving there is no data being sent from the moibile device. That's how it works with Chromecast and my smart TVs as far as I have found.

They can tell because whatever does the request to fetch the content sends headers with the HTTP GET request. and that announces the OS and browser being used including if it's mobile or not. As well as that these devices phone home and check for updates and Three have the option to detect on all sorts of things as they do deep packet inspection.

People complain when occasionally some badly written applications cause the tethering block to kick in, well that's what you get when you end up with lots of people cheating, they have to go further to try and block these people or discontinue packages if they become unsustainable.

They must be on the same network as you stated, so using the portable hotspot network will use the hotspot network to stream. If you're not using mobile data but home wifi then it's irrelevant to Three anyway.

So many one plan threads are opened,can this thread only be active instead jumping around in different threads, its getting confusing.

As I said in my post, I am not talking about cases like that. As I said I am well aware that for most apps, the "cast" is pretty much just sending the URL to the TV / target device. This device then uses its the wifi network (not the mobile network) to get the data. I know that.

What I am talking about is cases where the phone itself is getting the data, but using an official or unofficial app, you mirror your phone screen to another device. This is not app based casting as I have mentioned and you both talk about, this is essentially screen mirroring that the app will know nothing about.