[mbeattie]

They seem to miss the point that they shouldn't be tracking people "the old fashioned way" without a warrant either. You track people because you think they are guilty of a crime and you want to find the details. Not because someone might do something someday.

[arkem]

Police shouldn't need a warrant to observe people from public property (or in any situation where you don't have an expectation of privacy), in the same way that citizens don't violate the law by observing people or places from public property (barring stalking laws).