How do you keep control in the schools where some parents think that because they are paying high fees their child deserve all rights and wrongs?

It is the school policies and administration that decides such thing

A school can choose to be clear and firm about these policies ... regardless of money

Others fall on their knees for money !

As a teacher you can always set your rules and respect your profession. Teaching is a noble art of imparting knowledge and manners, if you can't deliver both manners and knowledge then it is better not to teach at all 

Those schools give high prestige to their teachers do not suffer this type of things. I believe on child centerd approach in a schools but teacher who impart the knowledge is also valuable. When child learn how to behave the parents automatically know what is the real phenomenon.

I think parents orientation a day before the opening of the school year can help solve this problem.  The school  will explain the entire scheme  of policy and the reason  why they pay high and where such payment go ( transparency  ) . Giving them enough idea about school goal  will encourage them to understand and  possibly extend their help to some extent. They will not think such unsound belief if they knew the direction of the school and how the standard of the school effectively implemented.

Rules and Regulations of the school !