Yes you are right, some in NZ do not need the tether bolt, but if it has it, they need to be used.. most baby capsals that i have seen in NZ do not have them, 50% of car seats (9kg-18kg) have them, and almost none of the boosters have them, I find my car seats fine without them, but wish my boosters had them as I notice when they outgrow the 5 point harness with only a lap belt they move around, and I do have H harness for them, but it still wobbles a bit.. (unfortunately my car still is the safest for these children as most of their parents don't use boosters once they hit 5, or if under 5 they are in those horrible foam boosters)