This video is one of many on youtube that describes the way residents of malibu beach who prevent people access into the malibu beaches.

<iframe width="960" height="720" src="http://www.youtube.com/embed/H_14Id-LOr4?rel=0" frameborder="0" allowfullscreen></iframe>

there is a dedicated website and guide to gain access to the beaches

http://laurbanrangers.org/site/malibu