This is hopefully a simple, but useful feature request:
I appreciate that there's a filter for jetpack_allow_per_post_subscriptions, however it appears to only default to unchecked. It would be great if it could also be set (programattically or otherwise) to unchecked so that posts would always default to NOT be emailed to subscribers.

In my particular preferred use case, I'm using some advanced indiewebcamp.com related tools like micropub to allow services like Instagram (via OwnYourGram.com) and Foursquare/Swarm to post directly to my WordPress installation. In these cases, I'm posting with a remote service (perhaps similar to posting via email) and don't have access to the post interface to toggle the checkbox so that these posts don't automatically email subscribers. Conversely, when I'm using the direct posting interface, it's simple enough to toggle the checkbox manually.

To put it another way: Is there a way to add a line of code to the subscription filter [https://jetpack.com/support/subscriptions/#filters] so that the checkbox is both available AND it appears checked automatically?

For the same reason, if it doesn't already exist, it would also be nice to have the ability to toggle the checkboxes on the JetPack publicize feature as well. (If this already exists, then it's likely easy to borrow the code to accomplish the same thing for emailing subscribers).

Thanks to the entire team as always for a great product!