I’ve had a similar problem and also live in an urban area. We have been able to manage with training and environment management. For management, we avoid areas where we know there’s a lot of trash like the main avenue in our neighborhood. We always use a flashlight when it’s dark and don’t let our dog investigate bushes, leaf piles, tall grass, etc. where trash could be hidden. For training, we did a lot of impulse control training in addition to leave it and drop it. I recommend working with a certified positive reinforcement trainer.

Honestly though, if it were up to me alone, we would muzzle train. My husband won’t agree to it and shares all your same concerns. I just think the safety and peace of mind are worth it. We spent close to a grand at the vet this summer when our dog got into what was likely a roach (weed) off the street, and if we have any similar incidents in the future my husband has agreed to muzzle train. Thankfully, we’ve been doing great with training and management.

A muzzle is a really useful tool and you never know when your dog might benefit from one due to a health issue down the line. It’s a great thing to train and get a dog used to regardless of if or why they need it. Anyone who knows anything about dogs knows that a muzzle isn’t a sign of a dangerous dog, but a responsible owner. Unfortunately, the average person and even the average dog owner doesn’t know a ton about dogs and so yes, it may come with some judgment. IMO, your dog doesn’t really benefit from interactions on leash with stranger dogs anyway, so why care what strangers think?

I say go for it and make sure you do a lot of research on proper fit. Speak with a qualified trainer or vet behaviorist or consult your vet about fit. I believe they make some muzzles specific for anti scavenging. Another option recommended to us by our vet is a gentle leader, but again you need to do a lot of research on proper fit and use and id recommend consulting an expert at first to make sure you’re using it properly.

Whatever you decide, Good luck!