There is a point. In the USA, not giving them permission allows your lawyer to fight the case on the ground that it was an illegal detention. Case law has set precedent that without reasonable suspicion officers cannot extend your detention in a traffic stop just to bring a dog in. Never ever give permission to search.

There is a point. I understand your friends point though. In the USA, not giving them permission allows your lawyer to fight the case on the ground that it was an illegal detention. Case law has set precedent that without reasonable suspicion officers cannot extend your detention in a traffic stop just to bring a dog in(Rodriguez v united states 2015). Never ever give permission to search.

I know he's your friend, but "don't take legal advice from your opponent" applies here. It may be true that they will inevitably find a reason to search your car. It may not be true that the ensuing search will be legal and hold up in court.

Of course, there is a nonzero chance you will not survive to see a court date, but that's a different policing issue.