Sure there are always exceptions, and it may have been just some unfortunate phrasing, all I know is that the phrasing explicitly didn't specify that the river

Sure there are always exceptions, and it may have been just some unfortunate phrasing, all I know is that the phrasing explicitly didn't specify that the river being unswimmable was at all an exception. It's like if you asked a lifeguard if it was safe to swim and they replied "Many people survive".