I'm thinking it is a bit more complicated than merely saying “Police should need a search warrant to even step foot on someones property”
A police officer should stick to public access sidewalks and streets when not in pursuit. This has nothing to do with not being trained to approach dogs. It has everything to do with an entitlement attitude by the cops that anything goes, including taking a short-cut across someone's private backyard with absolutely no authority to do so.
-PJ