If I were addicted to falling off roofs, I would try to stay away from them. If I found a roof with a fence on it, I would be less inclined to stay away from the roof (it has a fence on it, after all), and eventually I would find myself trying to climb the fence.
Here ends my contribution to this thread. I hope I have made my point clear to those that it applies to. @OP: I do not currently know of any filters for PC except one that relies on DNS, which you said you couldn't use. I hope you'll find something else, or find a way to do without it. Best of luck, and don't give up!