Or you could have done the same for free by setting the packet TTL on all client devices to 65. Carriers check if a device is using hotspot by looking at packet TTLs. Anything coming from your phone directly has a TTL of 64, but anything connected via hotspot loses one TTL hopping through your phone, so it comes through as 63 (or 127 for Windows devices). Overriding your client TTL to 65 means that carriers will receive the packet with a TTL of 64.
Yeah that's probably how it works, except I don't know how to actually implement all of that myself, and it was a one time payment for use on all my devices. The only downside is connection is through usb or bluetooth. If you are aware of a way to put my un-rootable phone in hotspot mode that sidesteps the up-charge, please advise. When I had a pixel with Graphene installed this was possible.
