Outside of bad porn or dim basements in Essex, being punished by a nurse is an uncommon occurrence. Except in prison.
What penalties do you suffer if you fail to attend an appointment with your GP? If you really take the Mickey, being struck off his list; but for missing the odd surgery? Perhaps some verbals from the practice manager, a sternly worded letter or two?
The NHS - repeat, NHS - staff who work in prisons have a more potent arsenal to draw upon, the privilege system. For failing to attend an appointment they can issue a formal warning under the Incentives and Earned Privileges Scheme (IEPS).
These warnings affect our level of privileges. How much money we can spend to phone our families. How often we can receive a visit. And, at open prison, when or whether we can work in the community or have home leaves.
Even if we put aside the legality of NHS staff using the prison's mechanisms of control, the question of its ethics is something I'd really like to see justified.