I fully agree with this statement, reason why I was pointing out that a lawyer opinion would be welcome.

I'm pretty sure that every people reading this topic on SwiNOG is not sure that such a request is fully supported by a law.

Now, I am not sure that some customers will recourse because one website is blocked from a couple of ISPs. But even, it remains an ethical question for the ISP to decide if they just carry bits and bytes (as the Swiss post carry letters) without worrying what these bytes are coding (as the Swiss post does; as of today they do not filter your mail to drop invoices and ads for delivering only personal letters and postcards).

2009/2/17 Tonnerre Lombard <tonnerre@bsdprojects.net>
Salut, Yann,
In my opinion it is not clear so far whether or not it is legal at all
for an ISP to block web sites. I think that blindly doing so -
especially by a dubious court order - might give customers a legal
right to recourse.