Why might it be incorrect to assume that an approaching vehicle with its turn signal on is actually going to turn?

• The driver may turn after passing your vehicle.
• The driver may have forgotten to turn off their signal.
• The driver might be playing a prank on you.
• Both A & B
  Explanation:

  "Do not assume the vehicle is turning. The driver may turn after passing your vehicle or may have forgotten to turn off their signal."