Damon said in an interview with the YouTuber Jake Hamilton that an artist wants to add a permanent bronze statue of Williams in the lagoon area of the Garden [in the spot where where they filmed the famous bench scene in Good Will Hunting].
“The idea being that if you feel alone you can go sit next to him, which I think is the coolest idea. It would be like the most beautiful installation and like such a tribute to that guy, who I think would’ve loved that.”
I don’t know the reason, but I’m giving them the benefit of the doubt. Presumably, that law was passed because people thought it was necessary.