Dave, if you wrap the barrel of the RCA with a few layers of teflon, doesn't that make it very hard to actually turn on and off the thread when releasing the RCA from the input? I agree the barrel on my WBT's has dropped off a few times, which is annoying, but one just screws it back on. The trick is to remember to turn it towards the input when releasing, otherwise you are possibly overtightening the whole affair, which I worry could actually lead to some damage. That aspect to me seems to be the biggest concern with this type of plug.
Nah, it just makes it smooth and with a little resistance. You should never be using enough torque on the locking barrel that it could possibly cause any damage. Just enough so the plug doesn't pull off the jack is fine.
I've also been using viscoelastic dampers on the barrels, they are really nice but my supplier changed things and the new stuff isn't working out. I have some carbon fiber tubing I've been playing with and this works even better, basically rings of carbon fiber that slip over the locking barrel. I may offer these as a stand-alone product to go with the WBT RCA plugs. I think that's the one thing WBT can improve, mechanical damping of the locking barrels.