Could the dutch and duchess of Cambridge be arrested?

ok so im sure we all know about the royal wedding. ive heard the queen can not be arrested but she is expected to follow the law. so is this the same for Kate and William? i mean at the end of the day, they have tried to make it as clear as possible to everyone that they want to be treated the same as everyone (not that everyone can have a 10 million pound wedding curtsey of tax payers!). for example if William randomly went to some guy and beat the Sh*t out of him, and shot him or something, would he be arrested like everyone else?