The WP source shows that
wp_filter_post_kses are passed data that's "expected to be escaped with slashes."
On the other hand,
wp_kses_data is passed data that's "expected to not be escaped" and
wp_kses_post has code that looks like wp_kses_data.
How safe is it to pass unknown (in terms of escaped with slashes) data to these functions?
Can the first set be preferred over the second or is preferring the second set safer?
Or is this a case where you absolutely need to know the condition of your data in terms of slashed?
I'm now figuring that if you don't know whether the data is escaped you could use
wp_kses_data( stripslashes_deep( $data ) ); and run the return though addslashes() if you need escaped in the end.