There is no reason a RVer couldn't dump their water just as a tenter.
We have two dish basins that we have used for a few decades when we had a dry TT or tented. When we washed the dishes, the water was tossed in a different area each time. Those same basins fit right in our sinks in the TT. We use them to dump the dish water in the toilet but they just as easily could be take out to the bushes as we did for decades.
Same with a quick navy shower, what is it a few gals? After you are done, drain it in a bucket and take it out to the woods.
That at least makes it so you are not dumping your whole grey tank ay once on one spot.
Better yet, know your capacities and usage and plan accordingly.