Lots of difference between trying to save a vessel and trying to save the vessel's crew. U. S. Coast Guard saves crews and will assist crews in need occassionally with fuel
or expertise. They do not have an obligation to save vessels.
With the number of really stupid lawsuits flying about I can see why a water taxi would not take the responsibility of taking a boat in tow. If there were damage to the taxi, he's responsible. If once, the skipper of the boat comes aboard, the skipper is injured or any of the taxi's passengers are injured then the taxi's captain
and owners are responsible. If the taxi captain
assists and the grounded boat is pulled off the rocks and later sinks, the grounded vessel's skipper might want to sue saying that the taxi captain didn't tow it off correctly.
We all consider ourselves good samaritans and will help vessels and crews whenever we can but if we are employed by someone else and somehow are using their equipment
and I'm on their time then I need to think about their liability. I've saved boats too and will again but I won't put my family
or crew in danger
to do it. I also won't risk my home and my assets and the assets of my family
to help someone who brings about frivilous lawsuits. I'm cautious.