Both Orin Kerr at Volokh Conspiracy and Jeralyn at TalkLeft recently covered the story of how the FBI is utilizing fake child porn links to get probable cause for home searches. This is from the media account of the story:
The FBI has recently adopted a novel investigative technique: posting hyperlinks that purport to be illegal videos of minors having sex, and then raiding the homes of anyone willing to click on them.
Undercover FBI agents used this hyperlink-enticement technique, which directed Internet users to a clandestine government server, to stage armed raids of homes in Pennsylvania, New York, and Nevada last year. The supposed video files actually were gibberish and contained no illegal images.
A CNET News.com review of legal documents shows that courts have approved of this technique, even though it raises questions about entrapment, the problems of identifying who's using an open wireless connection--and whether anyone who clicks on a FBI link that contains no child pornography should be automatically subject to a dawn raid by federal police.
Kerr isn't particularly concerned about the technique given the current 4th Amendment law concerning probable cause:
Did the government's affidavit create probable cause? I would need to look at the entire affidavit to know for sure, but just based on these basic facts I would think the case for probable cause is likely to be pretty good. I assume the FBI did not in any way broadcast their IP address or host anything on that computer, and that the link came in soon after the message was posted, so it seems likely that the only incoming web traffic request would be from a link other than from the message board. And given the context, this seems like an unlikely link that someone might come across by accident. To be sure, it's possible to imagine scenarios involving innocent links or some other break in the connection between the home and the possible evidence (unsecured wireless connections, for example), but my sense is that this would still likely create probable cause (again, a call hard to make without seeing the whole affidavit, just something that is likely).
Jeralyn had a different reaction:
Today it's kiddie links, what will it be tomorrow? Links to sites offering information on growing pot? Links to sites offering prescription medicaton? Links to sites critical of the Government?
Be careful where you click, you may be next.
While I agree with Kerr that probable cause law is pretty forgiving in this area, I'm still skeptical of the claim that the link click alone justifies probable cause for a search of a home. I think a limited warrant for the search of a particular computer or any computers using an IP address might be justified. However, without more, I think a warrant for the search of entire premises is beyond what is justified by a single link click. In this case, the warrant was for both the computer and any other child porn images around the house (which pretty much allows the police to search anywhere). I think the search of the rest of the house just isn't supported by the link click.
I do think Jeralyn is right to look at slippery slope concerns, but a couple of her examples are off the mark. Downloading of kiddie porn is in itself a crime (that's enough to "possess" the child pornography). That isn't true about reading other types of information so probable cause isn't supported in her hypothetical instances.