I rarely stay at LTVAs, normally just to visit friends who are there. I have never worried about using the shower tent at National Forest land or BLM land. My gut feeling is technically it is illegal to use them at all those sites, but nobody really cares about it. I know the LTVAs are much more strict than BLM. I guess I will stick with use it until told otherwise. I am used to Burning Man where the BLM will not allow a drop of water on the Playa, then I have to make a evap pit, which works in the summer heat but might not work well in the winter Q area, and is a pain in the ass.