A nudge changes the way options are presented while leaving alternatives available. Defaults, ordering, and reminders can influence decisions without issuing commands. The ethical question concerns the mechanism of influence, the chooser’s understanding, the goal pursued, and who gets to define a better outcome.
A nudge alters the setting in which a choice is made, for example by setting a default or making one option easier to notice. Some design is unavoidable, but that does not make every design equally defensible. The questions concern whose goals guide it, whether people can understand the influence, and whether declining is practically easy. A beneficial result can coexist with a process that exploits confusion or makes a formally available alternative difficult to use.