I'm beginning to wonder whether if those paranoid about IT security (when it's really unnecessary) has nothing much interesting in their lives to do. Therefore, they have all their energy wasted on the security. They can be friendly and even be very helpful to others. But when it comes to personal fellowship, there's a huge firewall around their lives.
Should they think they have DONE enough in Christian fellowship, the notion of a "living sacrifice" in Romans 12 is thus twisted by them.
To be a living sacrifice is certainly not about hard work in helping others nor investing in much labor. It is a transparent living that is Christ glorifying to others in every aspect of one's personal life. The notion "living sacrifice", works with one's life, not one's effort/energy/time/money. To insist otherwise, would clearly shows one's misunderstanding of "Faith in Christ" and "Grace of God" => trying to earn righteousness via works in disguise.
There may spark a debate: "But I must protect myself!!! It is unwise to just invite others to step on me freely"
My response: Nobody is asking you not to protect yourself. The question is why do you not have fellowship with others at a more personal/transparent level, as all in Christ should?