You just want to hope you don't get an issue where it needs downgrading or anything, as only way is to send it back to Apple, which you can only do on the developer program, I believe
That is correct, but you can then also open a developer account to be covered. I've also heard they will take care of it after a lecture from a Genius in the store. LOL, I would not suggest to anyone that does not have a deep background in OS X or Mac OS, or iOS to even be a tester as casual users and or beginners are not prepared for the outcomes that could happen. To many do not knowing what the are doing and the consequences, then they complain about it it. Apple beta broke my cars Bluetooth connection, etc or has bad battery life. That's what betas are for to fix issues with feedback from users, not complain on forums. I will say though all three betas are the best early release betas in a long time.