That’s crazy. They probably leave a mess for the authorities to clean up behind them, least they could do is pay for it.
Are you referring specifically to Kara and Nate? Because I also posted it in the National Parks thread, where your comment would have made more sense.
Check out this video from their trip to Vietnam, where they are removing other people's garbage from the water. Starts shortly after the 5-minute mark. Tznius warning.