I think I would mind if a dog peed and pooed in my yard even if the owner picked it up. The pee can burn grass and shrubs and you can't always get all the poo up sometimes. I wouldn't want my yard used as a toilet for other dogs. I guess if there are sidewalk grass edges or public trees and schrubs that would be ok but that is JMO...I think it's really an individual thing
(and hey at least your picking it up that's better than alot of folks!!!!!)