Canada, France, Italy and Greece allow Netanyahu’s overflight despite ICC warrant
(www.middleeasteye.net)
Shooting down an aircraft is far beyond standard airspace enforcement. Standard airspace enforcement would be to send fighter jets to escort the violating aircraft out of the airspace without conflict.
Which you've already said they can't do because the plane could just ignore them. What do you think is the next step when a violating plane ignores the fighters?