That's why all my shackles are drilled and safety wired.
Curious. Drilled where? Wired?
Since I don't have photo abilities, I will try to describe it.
You simply pass the safety wire though the eye in the shackle pin...some you may have to drill yourself, then wrap it around the shank of the shackle and twist it together. Don't forget to bend the end over so you don't poke yourself with the needle sharp end of the wire. Or...you can tape it.