I'm pretty shocked by everyone's low expectations of their children. How do you know they will lose things if never given the opportunity? I would just let them know that the responsibility is on them, they lose it, they don't have it anymore. On our trip my DD8 and DS who turned 7 on the trip both had their own backpacks with their own wallets and money, over 100 dollars each cash (they had been saving for over 2 years for our big family trip). Not only did they hold tight to their bags, but whenever they wanted to buy something, they just went up to a cash register and took care of it themselves. They didn't spend their money the way I would have, but it was their's to spend. The only thing lost in the 2 1/2 week trip was my DD's water bottle, apparently she was drinking out of it at some point in AK and set it down. When she realized later it was gone she was sad, but knew it was her own mistake. For the next week she just used drinking fountains instead. Give your kids some confidence that they are capable of taking care of things, otherwise they will pick up on the fact that you don't think they can and it will become a self-fulfilling prophecy later.