It's a fairly straightforward question. Someone uses a credit card to create and pay for a couple of months of a web site. That web site has child pornography on it. The web site employs nonsense URL and contact information; for example, one of the sites is http://foelonipwin-cmezixecvom.us/ and the contact e-mail is
firstname.lastname@example.org. Whoever created the sites knew the correct name, address, and credit card number of the owner of the credit card, though when s/he input the contact information for the owner, s/he alternately said s/he lived in Chile (in zip code "ucc16") or Bolivia (in zip code "nf897"). We're able to trace the IP addresses allegedly used to access the site and create the relevant e-mail accounts; they lead to two computers in the same state as the owner of the credit card but hundreds of miles away.
So there are two possibilities. One is that the credit card owner used his own credit card to create the sites (with his own name) but then input nonsense contact information and used proxy servers to access the sites and e-mails. The other possibility is that someone stole the credit card number and used it (alongside proxy servers) to create the sites. We check with the credit card company, and they tell us that the two charges on the card are relatively recent and that the credit card owner has not yet claimed that any charges on the card are fraudulent.
Assume all that information is disclosed. Should a magistrate judge authorize a warrant permitting the search of the credit card owner's home (and computer)? Does it create probable cause to arrest the owner of the credit card? In short, does that information create a "fair probability" that the owner of the credit card was involved in creating child pornography?
Judges Paez and Betty Fletcher say "No." Judge Ikuta says "Yes."
Everyone agrees, by the way, as to the truth. The guy's credit card had been stolen and his computer hacked. He didn't do anything wrong. At all.