I think this is a good idea, have a confirmation as part of ACF.
In some cases another users (which aren’t developers) uses the fields to insert/alter/remove data in posts, pages, etc.
Usually, these users don’t have so much “developer” skills, and deletes a field as a mistake. It already happened with a client, and is a little frustrating for the user (depending on the field deleted, a lot of work could be lost).
An idea is to do as the guys at MailChimp does: when deleting a block, a dialog appears. This dialog have an information about “how to delete a block without dialog”, which is “hit ALT to delete without asking”.
So, if a read this info, next time I know how to delete without ask.
By the way, I really LOVE ACF. Thanks, E!
PS.: I’ve tried to make the JS above work, but till now it didn’t work.