Some ports in Northern Europe send out warnings. The agent sends them. I’ve only seen warnings not to drop the lines.
Here is Steamship Mutual Safe Mooring Practice
Tugs’ lines should only be let go when the order to do so is received from the bridge. Once
the tow line eye has been removed from the bitts the tug should be signalled that recovery of the line can commence. The tug’s line should be lowered under control with the messenger tended carefully whilst the tug heaves in his line.The person tending the messenger must ensure they are standing clear of the loose messenger line flaked on the deck. Once the tug has recovered his towing line on deck, the messenger should be tended so far as possible whilst the tug crew are recovering it on deck.Towing lines and messengers should not be let go and dropped into the water as this can lead to problems as one of the following case histories shows.
Maybe they’ve never got a claim from a ship’s crew.