CrypticSwarm

I completely agree. It is entirely possible to secure with the appropriate API's.

Operations can be rejected by the server. If done correctly the client side can have an optimistic UI that is also secure. (Optimistic UI's don't need to wait for an ack from the server. They display local changes immediately and roll back if server denies.)

We played on a computer in the classroom. Just modified the one on that computer.

"usefulness" is a good way to put it. Had never heard the quote "All models are wrong but some are useful". I like it.