Jennifer Carroll MacNeill (Dún Laoghaire, Fine Gael) | Oireachtas source

"May" is a permission. "Shall" is a prohibition or a mandate. They are totally different things. "You may not" means you are not permitted to. If I say Ms Boate may not smoke in here, it does not mean she is allowed not to smoke but that she may not smoke, she must not smoke.