I say dont got for it. If you are tring to open up for the choke try to open them up different ways. Like try to guide the head with your forearm up on their forehead, etc.
The knuckles to the hinges of the jaw is a horrible thing to do to partners. In a big tournament, sure go for it. But to your "friend" and training "partners" I would never do it,.
When I first started Judo about four years ago we learned that right off the bat and then everyone was going for it. Worse few weeks until people started forgetting it while learning different techs.
I wonder if you could cause alot of damage that way to if you put enough pressure on the hinges. During a tournament (the third place match) the guy beat me with a baseball choke across the jaw line. I tried to fight through it but it ended up dislocating my jaw and causing me problems for nearly a year. It would clack all the time, get stuck all the time, and generally be kind of painful. I know the knuckles on the jaw aren't the same but I wonder if you could cause inflammation there and maybe knock it out of alignment.