It is definitely a worrying state of affairs when the only person allowed to dispute police engaging in illegal or unethical behavior is another policeman. The police are the mafia, and the only time they'll be disciplined without overwhelming evidence is when they mistakenly try to shake down another made man.
It's not like K-9s are uniquely to blame: the next generation of 4th-amendment violating technologies are already here, just waiting in the wings for judicial approval, or in some cases, to overturn previous rulings. And once they get even the most limited permission, these things (like infrared) will be used by the police as dousing rods to take them wherever they want to go.