Well in my case I can certainly tell you it was because I answered "that's none of your business" to all the questions they asked me. They were livid, and the

Well in my case I can certainly tell you it was because I answered "that's none of your business" to all the questions they asked me. They were livid, and the search they carried out was in an attempt at maximum intimidation. I'm a US citizen re-entering the US with a valid US passport. They have to let me in and I don't have to answer a damn thing (because the appeals court has already ruled they can search everything you have, including all electronics, without probable cause, I refuse to make their job any easier than it needs to be). On a separate incident at a separate border point (the Windsor-Detroit tunnel) they sexually assaulted my then-girlfriend (not a US citizen) during a very thorough body search which was also conducted for punitive reasons only after our refusal to cooperate in their search of our electronic devices (after they had already decided to deport her). (In that case I was driving a rented luxury car, so I don't think it was bus bias, I think it was just retaliation for insisting on our human rights.) US CBP is rotten trash.