I agree we should watch out for it, but I don't agree that it's irrelevant that it's legitimately useful today. Again: I'd be happy with a court order requirement, but not outraged if there wasn't one.

Drug dogs. Let's deal with that problem first, OK? Because we appear to have outsourced the 4th Amendment to dogs. I have a dog. My dog's jurisprudential capabilities are highly suspect.

Thankfully the Justices are aware that this is an issue. The beginnings of the oral argument in US v. Jones are relevant. The Chief Justice in particular is quite conscious about the issue you describe.

http://www.supremecourt.gov/oral_arguments/argument_transcri...