Granted, it depends on the park.
There is a park here, which is called a "waterfowl sanctuary", where most birds are banded and tracked, and some are owned by the city itself. (There is a flock of snow geese, for instance, and mute swans, many of which are disabled and could not fly so must have been placed there, also with leg bands on, as well as embden geese). They do not treat the nests/goslings/eggs well at all, but they do own these birds. It is a closed park; not really a park at all, and more like a sanctuary. You must enter through a gate. Only birds that can fly can leave, and no predators can get in. The geese that do not migrate during the winter are brought into captivity. Otherwise, they would die. Obviously there is no fishing because there is no lake WITHIN the park. There is a lake outside of the park limits, and many wild geese are there, but all the domestics or disabled or pinioned birds (like the flock of snow geese) are within the park at all times. There are only large, manmade ponds for the birds to swim in.
It's a nice place; lots of people visit. Those people stop visiting in the winter months. Even if the domestics were kept in the park during winter, they would surely die of starvation and freezing. People would not visit. As well, if those embdens were on the actual lake, in a wide open area where there were predators, fishing, and not such close regulation of them, I would be worried. Any time you have domestics that are not being truly watched over, protected from predators, fed daily (ACTUAL waterfowl food! They feed it, and grains, here) and taken in during winters -- if they are cold wherever you are -- then there is a problem.
I've hatched embden babies from a pair there, when I saw that the eggs had been disturbed. Well, actually, the female had originally laid behind a fence and the eggs were in front of it. Sold the babies to a wonderful home. They are indeed domestics. They are not allowed to hatch young because they are OWNED. They are not allowed to hatch young because they cannot be sure who they are breeding with, and no hybrids are wanted, surely, and they have limited resources when it comes to keeping them. The city does not own dumped domestics, who are allowed to breed with any bird they please, run wild, and are easy targets for predators, hateful humans, or as it has been said, fishing lines. Not to mention winters in which there will be no food for them. It is very rare that humans flock to geese in the winter as they do in the summer.
