Thunderbeast Arms sent me a description of their new 'low backpressure' suppressor option. I'm interested for sure. But in the description it says the direct thread version ships with a nord-lock washer.
I use these in other non firearm applications and they are a neat solution to the issue of keeping bolts from loosening. I just never consider the idea for suppressor mounting. I hate direct thread and go to great lengths to avoid it, but sometimes you can't. TB is a bunch of really competent people so I wonder if this application is a bit of magic on the issue of loosening threaded suppressors. Unfortunately the nord-lock application that shows torque values is down so I can't see how tight you would have to get it to make the washer work.
Anyway interesting idea.

GSL silencers have employed Belleville washers for the same reason. Either seems to be an effective solution for a problem I haven't experienced.

I historically wrap the threads with some nylon tape and tighten the silencer with a strap wrench, if it lacks wrench flats. I haven't had one come loose.

If the application of either of these washers enables hand-tightening and loosening without fear of walk-off, then that's pretty cool. Is that the idea?

I've been doing the plumber's tape thing, but I'm curious what your results would be if you try this out!