Typically I do not use a D ring or full check snaffle. Most of mine are loose ring and off set D's.
I have pulled snaffles and part of a headstall through a horses mouth, and yep, if you are at that point- you are in a wreck or getting in one.
On the occasions it has happened I was hopping onto someone elses horse that was having issues. Also why I like a brow band headstall with a throatlatch on a snaffle.
When I bought Cracker, my gray horse last winter, he had the bad habit of running off to the gate and trying to jump out of the arena. Glad I had a good snaffle rig on him. even though it did no good stopping him or pulling him around at least it kept it on his head..LOL.
I DON'T LEAD 'EM AND FEED 'EM, I RIDE 'EM AND SLIDE 'EM.