The forgiveness ethic I believe comes from Jesus Christ directly, and it's one of the few unique theological tenets of Christianity. That being said, very few Christians actually attain the level of spiritual development to practice it on the scale Jesus said was required.

Your point is that forgiving people are careless people, I'm guessing? I suppose, yes they are. The idea is that through understanding and forgiveness, caution will become obsolete. I'm not entirely certain how to reconcicle what Jesus said not only with my own common sense, but some of His own statements which appear to be self-contradictory.

For example, there is the famous 'unforgivable sin' he speaks of which is generally interpreted to mean somebody who knows better attributing the works of the Holy Spirit to other sources (the devil, science, random chance, etcetera). And he warns his followers if they ever cause somebody to turn away from their Christian calling, it would be better for them if they had never been born (something judgemental priests and ministers would do well to heed). And he warns all of us that if we harm children, the best thing we could do for ourselves is to tie a millstone around our neck and jump in a lake, because that's better than anything he'll have in store for us.

So the question becomes, what did he mean with "7 times 70 times" and what exactly does the forgiveness ethic require.

I personally think it means an openness to forgiveness towards others and for ourselves and a capacity to forgive that should in practice be limitless. I don't think the merit is in just pretending that nothing bothers us, but that should others seek forgiveness, we must be prepared to grant it, no matter what our personal thoughts on the matter are.