While sleeping, the simplest way to secure the bike is run a string from it and tie to the body part of your choice. Food in tent or hung. In a sketchy area in daytime, keep in sight. Cable lock good too. If in a store with a big vestibule(WM), I roll the bike inside. If going to a movie, they've always found a place to securely store it. If with a buddy and shopping, one will stay with the bikes.