If it screws and it is life support. I always put loctite on it. It may be a PITA later but I would rather struggle with it and know it's on there for peace of mind.
Definitely, I use blue locktite. No problem breaking it loose.
I actually had a shackle pin fall right off my harness. It was no big deal but I was about 70' up when it fell apart... left an impression.