I've never had a grab hook that wouldn't stay hooked? Usually the load, or just gravity, keeps it tight. A case of chain going slack and tight repeatedly?
My biggest problem is slide hooks, especially when you've climbed a tree, at the risk of life and limb, to put a cable around it so you can pull it over, then cable falls off as soon as you've climbed down and put some tension on it! Then you get to climb up again! Grrr!
One day I'll be smart enough to replace it with a hook that has a built in snap on it. I'm more likely to go the baling twine route too. I'd probably wouldn't drill it though.