"Sending Apple events to arbitrary apps With App Sandbox, you can receive Apple events and respond to Apple events, but you cannot send Apple events to arbitrary apps."

"By using a temporary exception entitlement, you can enable the sending of Apple events to a list of specific apps that you specify..."

The word at WWDC was temporary exceptions are temporary and just there to ease the transition to sandboxing. I.e. they will be REVOKED at some point in the future.