Moss,
This is interesting but, I may be getting confused by terminology. The term I was seeing that I thought met ANSI standards was auto-locking. That's what my Jake is; it locks automatically but it only takes a twist to open it.

I assume double locking means you have to do two things to release the gate lock, like push up and twist. Omega makes the Jake in a screw-lock, a Quik-Lok, and a 3 stage Quik-Lok.

So do auto locks meet ANSI standards or do they require double-lock or triple lock biners and auto-locking?

I've been using screw-lock Petzl OKs and have yet to find a lock loose, but now I'm wondering if I may need to replace them with double locks.

Edit:
I think I've found the answer to my question. The WesSpur site says that to meet ANSI standards for Tree Care Operations and Arborists, the carabiner must be auto-locking, auto-closing, and require two actions to unlock them and another to open. The also have to have a minimum breaking strength 5,000 lbs (23kn).