I expect your users would fire you when they found you'd blocked access to Google.
And they would sue you for gross negligence for decrypting their ssn when access company payroll and cpni data
May I suggest that playing Junior Lawyer on nanog rarely turns out well. These filter boxes are typically used on private enterprise networks. Companies have broad latitude in what facilities they provide to their users, and the rationales for filtering run from keeping out malware to keeping dimwit guys from porn sites that are fodder for hostile work environment claims. Your employer alrady knows your SSN and payroll data. Unless, I suppose, you're using your computer at one job to moonlight at another, but you're not going to get a lot of sympathy for that. There are also ISPs that provide intrusive filtering as a feature. I wouldn't use one, but I know people who do, typically members of conservative religious groups. R's, John