The police never searched that car.
Can you imagine being stopped for a crime, and the police never trying to search your trunk?
And dogs are not infallible. They make mistakes every day.
This is correct. Just because a bloodhound is used doesn't mean that it's some magic entity. They have to be properly trained, and even then they have off days.
"And dogs are not infallible. They make mistakes every day."
This is true. I once worked with a dog trainer. I learned that the dogs can't sniff for long periods at a time. They get tired and their sniffer starts wearing down.