My relative came up behind me once in the old squad he had and didn't think I saw him even though I waved at him. Then the next time I saw him I told him that I knew it was him behind me. He asked how I knew and I said simple, you can't outrun the police scanner. I heard him meet with a fellow officer at the pumps and I drove by there on the way to get dinner that night when he pulled behind me. He followed me for a ways and then turned around thinking I didn't recognize him. LOL He never tried it again. He also said he would start using his phone more so he could hide on me, I told him nice try I have a phone and friends too.