Off-leash dogs in my neighborhood are super annoying ㅡㅡ

Dog owners, those guys are out here crawling out like cockroaches every single day, letting their dogs run around off-leash. It's pretty much an official (?) off-leash spot. It's not a dog park, it's a park with exercise equipment, and if you look closely, there are people exercising nearby too... They probably know it's illegal, so they only come out at night to let their dogs off-leash. Reporting it doesn't seem to do much, so I guess the only option is to take pictures and spread them around...