Here is a thought experiment.
Alice is 18 years old, and wants to get into a nightclub where you have to be at least 21, so she steals 21-year-old Bob’s ID card. Alice is an identity thief.
Alice uses the ID card to get into the nightclub, as the bouncer only looks at the date of birth to calculate the holder’s age. Age is a protected characteristic. It has not been taken from Bob, as it is inalienable: Bob cannot give his age to anyone else. Alice is an identity thief.
Alice pretends to be 21 throughout the year, sometimes getting into age-restricted clubs, sometimes not, sometimes using Bob’s ID card, sometimes keeping it in reserve, sometimes leaving it at home. Alice is an identity thief.
Perhaps Alice doesn’t do any direct harm to others, including Bob, or even to herself. Perhaps there are no wider social consequences, or only good ones, as one club’s security is tightened up. Yet, Alice is an identity thief.
Perhaps Alice fails to get into any club, or never even attempts to make use of her claim to be 21. Perhaps all she takes from Bob is a copy of a code verifying the holder of the code as 21 years old. Nevertheless, Alice is an identity thief.
What, then, makes Alice an identity thief? She uses a value of a protected characteristic, age, that does not belong to her (21 instead of 18). She takes this without asking, but as a class attribute, Bob cannot give permission, and as an inalienable attribute, Bob cannot give it away, nor even the whole class of 21-year-olds even if asked. So, to be clear, identity theft can be of a non-unique attribute belonging to a class of people. It does not need to imply loss or harm or even attempted deceptive misuse.
Alice is an identity thief.
Is there a way for Alice to get what she wants without being an identity thief? (there is one in this scenario that will not work in others)