A 4 year old really is getting too old and to big to be using a pacifier especially in public places.
At 4 years old you should be getting rid of the pacifier at least during the day time and by age 5 the pacifier should be gone altogether.
Although in reality the pacifier should have been gone by age 2 or 3 at the latest.
The child would not be able to take the pacifier to kindergarten with them and if they did the child would be made fun of by other students in school.
So you really should take the pacifier away from the 4 year old child because they are getting too big for pacifiers.
There's really not much need for a pacifier past age 2 years old so ideally the pacifier should be taken away before age 2 when the child doesn't have much fight to put up about it.