Thanks for the pointer to the release notes... I hadn't read them for the beta yet (and justifiably, because I hadn't installed it anywhere!) Given that the install/upgrade updates the schema, thus requiring Schema Admin for the AD, it's even more shocking that it has been 'accidentally' installed in production! Perhaps to protect more against this, there should be an extra screen in the setup that appears, when the product version = a beta, requiring one last extra acknowledgement that you're installing it in a lab or are a TAP customer.
Having read the release notes now, I noticed there's at least one new thing, the default disabling of streaming backup, that's also using a registry key. I don't know if this suggestion could be taken into consideration at this point in the beta, but it would be nice (even though it could be considered trivial to add a given registry key) if this was also available in powershell (Enable-RemoteStreamingBackup?) Perhaps that could just be a .ps1 script that adds the registry key... in any case this would keep with the theme of relatively self-documenting, scriptable, powershell commands that encompass everything that can be done or configured in Exchange server.