Cody,
The weight of the car needs to be sufficient to close the knuckle. When the knuckle contacts the back of the coupler body on the mating coupler, it is supposed to fold and close. You only need one knuckle loose. The other can be locked. BUT, there needs to be sufficient weight to keep the car in place and fold the knuckle. If not, the open knuckle will easily push the freight car. Not so much with locomotives, but definitely freight cars. As you will see in my video when I post it, the knuckle does move VERY freely, but there is always something that can cause the knuckle to not close properly and in N-Scale it is the weight of the car.
Now if I was to produce these for just myself, then there would not be an issue. I do not mind fine tuning the knuckle to work properly. But for the mass market, no way. There would be so many complaints about it, that it would most likely not even sell.
No way you can use an under the tie magnet either. The steel ball naturally falls with gravity and that is what locks the knuckle. Also, the magnet under the ties is to far away to have any effect on the ball. Nope, has to be the wand. All couplers are going to have a negative response for some reason or another. Heck if you made a fully prototype operational coupler, modelers would have an issue that you had to lift the coupler lift bar. So for this one, it is a magnetic wand.
The market for these couplers though would be the fine scale modeler. But still, for those with large fleets. There is to much fine tuning that needs to be done to make this a viable alternative coupler.