We camp regularly at a private campground where there is only water and electricity, We often will leave rig sit there for weeks at a time and use it as our weekend lake house. We keep our grey water grey and it gets let out at a slow rate and never have any odors or standing water. Black water gets toted off or dumped after we leave. If I’m staying in a normal campground while traveling then no absolutely not.
My first rig had a macerateor that would slowly pump into exhaust and burn it off. The heat chamber was rusted out so I removed the whole system. I always wondered if it would let out brown smoke going down the road.
Trains used to just let it out on the tracks.
RVing is always an adventure, it just might not be the one you're expecting.