Wofati, earthbag, earthen floor, cob and Radon

Has anyone on here considered radon testing and mitigation in their construction projects?  I think that this would be an extremely relevant topic to structures that are earth bermed, like a wofati, earthbag houses, and to earthen floors. I also wonder how much, if any, cob inside a house would add to radon issues. Radon emits naturally from the ground, so typically in an area where radon may be suspected, new construction would implement things such as having a plastic barrier between the ground and basement or crawl space, sealing the basement up good, and placing passive radon vent pipes from the basement to the roof.  These are all things that can be done to a normal stick built or log house, etc. it’s a little harder to do after you’ve built and discover that your new home has a radon issue.  But what about a house where the entire thing is surrounded by potentially radon emitting earth?  What should be incorporated into the design right from the get go so that we can prevent having an issue down the road?

Radon is much heavier than air and I think it's spread around a house from the basement by forced air heating systems.  In a wofati, I would think it would want to fall out the doors when you open them.  But in the winter when you're closed up, it could accumulate.  The normal passive (or fan based) system could be implemented in a wofati, just go out through one of the window walls.  Passive may be harder to accomplish depending on if you can develop a chimney effect.

The above info is based on conjecture plus having a radon system in my last house.

At least with an Oehler design (unless I'm remembering wrong) and with a lot of earthen/cob floors, a plastic vapor barrier is put on the floor so radon would be rather limited. A wofati is built on/above grade so there's no accumulation. Being totally air tight for extended periods is pretty uncommon as well.