WHile I don't expect privacy, I want it, and I want other people to really think about it and not want public surveillance as well. We should have some expectation of privacy out in public and not allow a loophole of "oh, but we were looking for someone else but also saw you", it's a huge loophole with essentially no limits. A warrant should cover one "thing" a person, group, etc. Anything else grabbed in the process should not be admissible in court or even be used by the police.