There are some celebs who believe it or not HAVE been pressured by their managers and reps. I also know of many everday Joes and Janes who's family or significant others pressured them. Sick.
These were cases of suggestive pressure, financially gaining pressure, or psychological pressure.
But when it's you going under the knife, even when someone else is insisting and is even paying for the procedure what do they do if you do not agree? They cannot sign your releases for you. They also can't physically restrain you or hold you down so the surgeon can operate.