Kinopio was designed to save even without a reliable connection.
If you have Kinopio open and lose connectivity (e.g. going through a subway tunnel), you can continue editing your spaces as you normally would. Once you're online again, the changes you've made will be sent to the server.
Features that require active connectivity to a server, including collaboration, will not be available while you're offline.
Full offline support, including the ability to open Kinopio while offline is on the longer term Roadmap