I have this idea and it is probably crazy but...

[Optimistic Paranoid]

Mo's rig still makes sense to me in regular dirt. Certainly not in clay. We have a great plenty of that here, and I can testify to its water-holding characteristics.

I agree with you that it would probably be fine most places.  But even when we are not talking clay, but rather rocky or sandy desert, it's probably not going to be a good idea due to the absence of plant matter and microbial activity in such soils.  A desert can be a surprisingly fragile ecosystem.

And Mo was talking about boondocking in AZ, IIRC.