I love dogs, but what would you have done?

So I'm sitting in my living room watching the game on Sunday. Then I hear the sound of leaves rustling in the front yard. I live in a typical suburb. Houses are next to each other. Property not too big. Sidewalk runs across the front of the property. I go outside and I see a guy standing out on the sidewalk but he's letting his dog explore my yard where it meets the neighbor's yard. He's on my side of the property where there are a row of bushes. He has the dog on the leash, but the dog is at least 10' into my yard sniffing around and pushing through the bushes. I'm thinking to myself "WTF?"

I love dogs. I really do. But I would think there would be some common courtesy involved when walking your dog and NOT allowing them to explore a stranger's yard without permission. Here's what also ticked me off.

I ask him nicely "excuse me, can I help you with something?" He looks up at me like nothing is wrong and points at the dog and mumbles something like "he's gotta go" or "he's doing his thing" or something of that nature. At that point, I was pissed. I said "not on my yard". He then gets embarrassed and walks off and I proceed to tell him to "please control your dog, thank you". I used "please" and "thank you", but wasn't exactly nice about it. I was already aggravated by his ignorance. He had nothing to say in return. No apology, no nothing. Now if the dog was on the sidewalk, walks by and lifts a leg and p1sses on my tree, I have no problem with that. You can't really control that. But this guy let his dog lead him into my yard and the owner thought that it was OK.

What's the expectation here? I know that many of you are dog owners. What would you guys do?