I spoke with a National Park Ranger who was a native of El Paso and Hispanic. He told me he was coming back from visiting family in the Rio Grande Valley and was stopped by Border Patrol. He had his uniform hanging in the back of the car and as a curtesy told the BP he had a weapon in the car and a concealed carry permit. The dog hit on something in his car and they dragged him out into their offices and he underwent intensive questioning while they searched his car. Turned out the dog had a false positive hit and there was nothing there. The BP only let him go when he'd reached the end of his rope with them and told them he wanted to speak with their Supervisor and have him or her contact his Supervisor with the Park Service.