Question about the London mayor and public transport?

If the Mayor doesnt have special privileges on public transport, then why? After all, he is the mayor! And if he only has the same rights as the public, is that why people are complaining that he didnt get a fine? Is it because then he will get a criminal record (like the European visitor who got a criminal record when she forgot to activate her oyster card?) Is it because he cant stand for Mayor in 2012 if he has a criminal record?