Is it just me, or is the "black tank flush" port a newer idea anyway? We didn't have it on either of our previous campers, and I don't recall it being on any of the campers we used when we were younger. I don't think there's anything wrong with adding water for a black tank flush, but I also don't think there's anything wrong with not doing it. Whatever floats your boat (or your poop).
Now if all you ever did was drop solids in the tank, that might be a different story. But who doesn't use their toilet for #1 and who doesn't add water before a #2. Heck, I even add water before a #1.
