My kids, although they do not know what an "SLA" is, are keenly aware of the concepts. At any given time, their computers are scanned for spyware, viruses, and their Internet history is checked. Temporary Internet files are manually verified. They do not have admin rights. The computers are in a common area. They have been told and reminded that the presence on any inappropriate material means the immediate wiping of their computers. I use Windows for them, but one kid is familiar with Linux (the machine dual-boots) and likes it. I use McAfee and parental controls. However, the best tools are your own diligence and vigilence. Do not leave them in a closed bedroom. Keep the computers in the open areas. Although there is a reasonable expectation of privacy in our home, one a computer is not one area where there is. I realize your question is on Linux, but parental oversight runs on any operating system.