apple locking Ipad to carrier

I would really like to know what right Apple has to lock my ipad to a network provider/carrier.

My brother gave me his Ipad Mini 2, thanking you very much, to discover that it was locked ti he current provider EE. I want to use 3. I questioned 3 about this wa told that ipads are generally not locked to any provider but the only way was to put a different data sim in and discover what would happen.

Duly paid £15 for a data sim and low-and-behold it was locked to EE. After doing a bit of digging my brother contacted EE to see what the score was. They told him that 'They' don't lock the pad to their services but Apple do! We fould at that you have to request EE to request Apple to remove the lock from the Apple database.

What right has apple got to lock my property to any system? What right do they have to know which service I am using? Unless I tell them any of things I cannot see what right they have to pry into my private business and contractual obligations.

And then to not allow me to tell them to release my system from a given provider?!?

I have a feeling that secretly carrying these action is an invasion of my privacy and possibly against my personal human rights.

One very angry 1st time apple product user.