I've found some old family journals and I have been working on transcribing them to word documents. I found an entry from my grandpa during a road trip out west in 1934 that I really wondered about:

"At 11:00 o'clock, we neared the California line and saw the cars being stopped for inspection. We finally stopped at the Oregon side and ate 3 apples we had in the car. Our Myrtle leaves had been packed in the roll of bedding and out of sight. The inspectors stopped us, looked through the suit cases, examined the Begonia, but did not open the blankets, and we passed through the station without trouble'

They used to stop and inspect cars across state borders?? Does anyone know?