  We identify rotations of the polarization angle in a sample of blazars
observed for three seasons with the RoboPol instrument. A simplistic stochastic
variability model is tested against this sample of rotation events. The model
is capable of producing samples of rotations with parameters similar to the
observed ones, but fails to reproduce the polarization fraction at the same
time. Even though we can neither accept nor conclusively reject the model, we
point out various aspects of the observations that are fully consistent with a
random walk process.
