The SCOTUS disagrees with you. There is no such requirement to "take steps" to have an expectation of privacy. The deciding factor is if the situation is such t

The SCOTUS disagrees with you. There is no such requirement to "take steps" to have an expectation of privacy. The deciding factor is if the situation is such that the "community in general" would expect privacy to exist in the type of situation being examined. A good example is how the SCOTUS ruled that there was an expectation of privacy regarding IR cameras. Very few houses have any kind of real shielding against IR leakage, but the use of IR cameras was still rare enough that it would be unreasonable to expect the average citizen to take specific steps to defend against that intrusion. The average citizen expects they already had a reasonable amount of privacy. The implication, of course, is that this is something that can change over time. If IR cameras became commonplace, it would be reasonable to assume a lack of IR privacy. At that point, it would indeed be prudent to expect people to take additional steps toward securing their privacy. This "community standards" distinction is particularly relevant re: data mining, because relatively few people have any idea how powerful the table JOIN can be, and as such DO expect a certain amount of privacy regarding their data.