'civil liberty' in an anarchist society

one area of the private defense/court discussions that i never hear talked about is how will civil liberty be protected from infringement by private security agencies. can anyone lay this out for me? its the one area that i am having trouble figuring out when discussing privatized defense and law enforcement.

while its 100% true to say that governments do not really protect a right to be free from unwarranted search and seizure and unlawful arrest, (among many other things) but it is at least SUPPOSED to be how it works.

what i am getting at…is what will protect us from a private security agency/defense force/company from monitoring our emails, phone calls, raiding our houses without probable cause, using rendition, torture, etc, when they are attempting to prosecute, say a murder, etc??

They wouldn’t have any special immunity when using aggression. If a defense agency breaks down your door at 2am and shoots your dog and you (and your dog) turn out to be innocent, they would be treated no differently than if a private citizen did the same.