I've known someone who has this as a hang-up and heard of it in other people, but I don't get it at all. I get that people have their things, but dogs go when they want to go. It would be different if it was poop and you weren't collecting it, but you do. I think it's good to apologize, even if it really isn't your fault, just out of respect. I think that was the right thing to do and good for you for doing it. I guess if it were me I would either walk your dog on the other side of the street or go a different route to avoid that house. Like I said, everyone has their thing and it it means as much as it clearly does to her the polite thing to do is just take steps to avoid it happening at that house. Personally, I think it's an incredibly silly thing to get all worked up about.