Parallel construction is foremost a run-around of the "fruit of the poisonous tree doctrine".[1]
It allows law enforcement to use methods that might amount to illegal searches, and then avoid judicial scrutiny of those methods.
See, for examples of such methods, Stringrays, "persistent surveillance"[2] aircraft, and NSA information sharing agreements.[3]
"Plain sight" doctrine isn't going to apply to these methods. You aren't allowed to use deconvolution to look through frosted glass and call it "plain sight", just as you can't use methods not in typical use to abuse WiFi as an imaging service. You can probably use WiFi traffic metadata, however, just as you can retrospectively use cell tower data.
It allows law enforcement to use methods that might amount to illegal searches, and then avoid judicial scrutiny of those methods.
See, for examples of such methods, Stringrays, "persistent surveillance"[2] aircraft, and NSA information sharing agreements.[3]
"Plain sight" doctrine isn't going to apply to these methods. You aren't allowed to use deconvolution to look through frosted glass and call it "plain sight", just as you can't use methods not in typical use to abuse WiFi as an imaging service. You can probably use WiFi traffic metadata, however, just as you can retrospectively use cell tower data.
[1] https://www.law.cornell.edu/wex/fruit_of_the_poisonous_tree
[2] https://arstechnica.com/tech-policy/2014/07/a-tivo-for-crime...
[3] https://www.engadget.com/2017-01-12-obama-expands-the-nsas-a...