How are optimistic rollups secured?

Hey! I'm the OP, publicizing this here today because we have set up a bug bounty for the system described in this thread!

We're paying 50k for people that are able to completely break the system, and 5k for minor problems. Details here: https://immunefi.com/bounty/optimismcannon/

There will also be a call next Tuesday where you can come ask your questions: https://immunefi.com/bounty/optimismcannon/