Hi, has anyone used the trunki booster seat for a 3YO? It says on the website they are for 4-12YO but I'm thinking this is a safer option than nothing for taxis abroad, no? Otherwise, what are you supposed to do, take your car seat? We are travelling to Paris on Eurostar and my DH is disabled, so I will be carrying the luggage for all of us!! Don't really want to lug a car seat aswell.