It's a very interesting outcome but it's clearly directed more at Traffic Sense rather than the actual "All you can eat" claim.
On the plan details it did clearly state and in the terms and conditions that you had a limited "hotspot usage" and it wasn't the same as phone usage.
It's obvious most P2P downloads are illegal it's a high percentage maybe not as high as "99%" as what Three UK claim, as many game updates which was mentioned in the complaint use P2P with the addition of Linux Distributions. P2P tend to be ideal for "Large Downloads" rather than downloading and hammering one server you have the ability to upload and download from different servers and locations (Peers and Seeders), I back Three up on blocking P2P for the reasons of people hammering the network and affecting the ability of other users.
As for the "All you can eat" it implies unlimited but a business can make a decision to exclude a customer from there services at any time, I think the soft cap of "1000GB" which is only in place to "Identify Commercial use of the services" is a little harsh, I don't see any other network offering near enough 20GB+ especially without been throtled.
Always remember though a Mobile network will never fully be able to support "unlimited" for everyone, there will always be speed caps, some sort of limitations in place, there just isn't enough spectrum available to support it.