This only applies to public parks, but I wrote about this problem here: [Forumosa - Taiwan's largest and most active Taiwan-oriented global online community in English … 8#p1021088](Where do you let your dog pee? - #21 by John
Once you have confirmation from the mayor’s office in writing, you can ignore all the bullshit anyone throws at you. Let them call the police, just show them your letter and keep smiling.