[Brian]

We used to have a preference/behavior like this in place, but it caused a problem: folks would opt into sneakypeeks without knowing exactly what they were, or they'd forget to turn that back off once the next "real" release came out.

Some period of time later, we'd get confused/angry emails about the annoying daily updates and/or the sneakypeek time bomb kicking in. We actually lost some customers over stuff like this.

Which isn't to say that we can't do something that works better for you - it just can't be visible in the preference pane. :-)

(This seems like the kind of thing where there may be a hidden preference that would do this via defaults write. I'm honestly not sure - if you email the support ninjas, they can investigate...)