Chiappori, Levitt, and Groseclose try to measure how important it is for the kicker to kick to his favored side, add center kicks, etc., and look at how professional players actually behave. They find that they do randomize, and that kickers kick to their favored side 45% of the time and goalies lean to that side 57% of the time. Their article is well-known as an example of how people in real life use mixed strategies despite not being mathematically sophisticated.