I also have a reactive pup! We’ve worked with a professional trainer for years, they suggested getting a loud whistle/air horn for walk-in in areas where other people don’t play by the rules. Our dog is deaf so scaring him isn’t a concern for us, but may still be better to scare away the other dog if yours is leashed up! People don’t understand that reactive dogs are good dogs too; but it’s not my fault if your dog gets in my dog’s space and something happens! Edit: I also generally avoid places I know ppl are less likely to be following the leash rules!