Exactly. In an opt-in system, enabled means "they displayed a preference against incidental access to porn" and disabled means "they've never bothered to change it". In an opt-out system enabled means "they've never bothered to change it" and disabled means "this guy irresponsibly exposes his kids to sleaze, and spends his free time downloading demeaning hardcore pornography".

We all know that, at some point, the status of some poor schmucks ISP filter is going to be used as supporting evidence of their lifestyle against him or her in court.