The point is: just because it is easier doesn't mean the rules have changed. It is still and always has been legal for someone to track you driving around town, be that by paper and pen, Polaroid, or streetcorner mounted camera with wifi.
Of course, the "rules" have indeed changed. It's pedantic to the point of ignorance to only consider laws and reject the context in which those laws were made (pre-wifi-enabled-streetcorner-cameras). The words on paper might not change, but a rule effectively changes when the environment changes around it. Consider also: every other legal issue that intersects with technology.
You realize that you contradict yourself in the same sentence? That's the kind of thing I tell people who ask me "Is so-and-so (technically very hard) possible?": "Most things are possible with enough time and money".
The fact is, technology makes previously impossible things possible, and previously difficult things easier. The law should absolutely account for that.
The Supreme Court's decision effectively said that having to use people to tail suspects or whoever put a brake on the government. The GPS trackers removed that restriction. They proceeded to rule GPS trackers without a warrant as unconstitutional.
See: http://www.supremecourt.gov/opinions/11pdf/10-1259.pdf.