I don't mean to be provocative, but I had thought there was some question about the statement "For an ISP to be scanning all this communication between private individuals that the ISP is not a party, that is unquestionably a wiretap." If no person is listening (reading), and the router (or some appliance) is just silently replacing flagged bytes with 0xff (or dropping the packets), does that violate privacy? (Or, more specifically, the Electronic Communications Privacy Act?) It has interfered with the reliable delivery of my mail, but nobody knows about it, so it's still private.

If the system informs somebody that my mail contained illegal content, then it sounds like unreasonable search, like body searching (for drugs) everybody who enters a stadium concert. I am pretty sure that it has been established (in some states, anyhow) that searching an entire group without specific cause for suspicion is not admissible as evidence. In the drug case, you couldn't be charged (well, convicted) legally, but you could be barred entrance to the concert.

I'm as against it as the next guy, but it's important to know where the legal eels have wiggle-room and, to an non-lawyer like me, assuming everyone on the internet collects illegal images is pretty similar to assuming everyone going to a Ted Nugent concert is carrying drugs (not expressed as a percentage, obviously). Can anybody cite a reliable reference here?

He's actually a leftwing nutcase in this instance though they can be difficult to isolate when tarring with the same brush - still looks like chicken after the fact.

I used to read comp.lang.ada -- maybe he thought it was comp.lang.lolita?

I believe it still counts as a wiretap even if no human actively watches what it's doing. Someone deliberately ran the program, and it probably generates log files that can be read later – like a system that automatically records phone calls. The whole thing is very similar to what Phorm does.