You are correct to say that you can't commit a trespass by observing someone in public. However, trespassing is not an exclusive test as to whether a search is permissible (though it was the applicable rubric for Jones). The Katz test still must be applied, above and beyond the trespassory test. The concurrences in the Jones opinion state "at the very least, “longer term GPS monitoring in investigations of most offenses impinges on expectations of privacy.”

Swap "GPS monitoring" for infrared, EMF, video, audio tracking, whatever those planes are doing, and I think we are at the same level of "impinge(ment) on expectations of privacy."

Is it your opinion that Alito and Sotomayor are barking up the wrong tree? Is this sort of extensive (i.e. multi-modal (visual, EMF, etc.)), and evidently prolonged, monitoring not an impingement on typical expectation of privacy? Sure, this isn't a trespass, but if a private person was doing this to you, wouldn't you want to call the cops? (Oh, wait...)