The details on the "tax" are still very sketchy so I don't know for certain. That said, I suspect that the only way to be certain of being indemnified will be to pay up. We know that the RIAA are willing to start sending threatening letters based on dubious "evidence" and then settle out of court so they would only have to "believe" that you were infringing and you'd up for a suit.

It will take a while to see if anything comes of this but the probability is unfortunately quite high that the idea will not just go away without a fight from those of us who "get" the issues involved.