Post by email always to draft

You will indeed need to use the shortcode, as there is no way to change the default status for all future posts at once.

How about if we hack the plugin’s code for this? There must be SOME way to intercept posts being pushed by Jetpack/post.wordpress.com to the site..

this should be marked as [denied] instead of [resolved]

On a different thread, someone suggested using the Postie plugin.