A few years ago I bought myself my own lunch box. I'd occasionally use one of my kid's lunchbox when need be. Usually though they'd be dirty from them using them and not taking care of them. My kids were plenty old enough to clean their own lunch boxes. So, I thought I'm going to buy my own. Only I needed to get one that my kids wouldn't see as the only clean lunch box in the house to use. I bought a big honking pink lunch box. Not my favorite color, but DEFINITELY not either of my kid's either. Neither of them would be caught dead carrying my lunch box and that was my plan all along.
Sorry for the crappy picture, but you get the idea. Many fun choices from which to pick. Star Wars, Spiderman, Hello Kitty, Mario Brothers and even Pink Disney Princesses if you need to keep your hubby and kids from borrowing your lunch box.