Restraints come in various descriptions. Restraining a patient can be as simple as putting all 4 side rails up on a bed. I will typically ask for this order if I have a confused patient at risk for falling out of bed. Whether it be a head trauma or elderly dementia, 4 side rails are my friend in these cases. Much easier to ask for the restraint order than have the pt climb out of bed and crack their head open on the floor!
Beyond 4 side rails, you can place wrist restraints, ankle restraints, and lap belts on a person. All these DO keep a person "tied" in bed, and you could say it's always against the will of the pt, but it IS for their own safety. 99% of the time I'd say the pt is not mentally competant at the time restraints are needed to make an informed decision regarding their care.
Take into consideration a guy named "Fred." Fred was admitted to your unit with a dual diagnosis of Etoh withdrawal and schizophrenia and is, to put it simply, CRAZY. He's fighting with the nurses, constantly forgetting his own abilities, and consequently has managed to climb out of bed and fall multiple times despite the watchful eyes of nursing staff. One night inparticular he's written to have 4 side rails up as an attempt to get into bed. The nurse finishes her assessment, is POSITIVE at that time that he's ok, and leaves the room to see her other patient. As soon as she leaves there is a loud BANG heard from the room. The patient has crawled OVER the foot of the bed and fell flat on his face. Ok, that didn't work, time to restrain his wrists to keep him IN the bed. Great. Except now he's doing a wonderful impression of the exorcist as he's constantly sitting straight up then flopping back in bed. The nurse attempts to calm him, just to have him kick her straight in the sternum. Ok, 4 point restraints now! But he's still flopping around in bed, threatening to harm himself (despite doses of ativan, haldol, and risperdol) so a lap belt was added and IM haldol given.
NOW the patient, AND nursing staff are finally safe. When you get patients like this on an impatient floor (ICU step-down), restraints can be your friend!