This plugin, when combined with Subscribe2, always sends out two emails for every post. The solution as presented by Subscribe2's author is to add:
add_post_meta($p, "s2mail", "no");
after inserting the post. Would you be willing to include this in a future release? (as I obviously dislike hacking plugins)
If you don't want to mod your plugin to work better with another, which is understandable, would it be possible to not just copy, but SET, post meta with the plugin option on the Options page? There's already a box for copying postmeta. What about adding the ability add meta that can be set as well?
If you want to copy custom fields with posts. One custom field per line.
my_foo_meta would just be copied, s2mail would be set to no?