1) Obviously you can't be trusted to handle your own ID card, because you could lend it to someone else or manipulate it in some way, so there should be a trusted guard with you at all times to manage your ID card for you and hand it to the shopkeeper.
2) Obviously you can't be trusted not to try to influence or attack your guard, so you must be kept in handcuffs for your own safety.
3) Obviously you can't be trusted with acquiring unapproved tools or meeting unapproved people who might enable you to break out of your handcuffs, so the guard must only allow you to communicate with approved people and buy approved products.
Conveniently and profitably, this also puts the company supplying the guard in a position where they can sell access to their control over you (as a consumer and as a source of experimental data) to their trusted partners.