> Haven't stalking and surveillance always had a different interpretation despite mostly taking place in public?

Yep. And dragnet surveillance has (pretty much?) always been illegal in the US... but it takes the courts an awfully long time to notice the new dragnets the cops set up.

For example, despite the fact that the third-party doctrine says that cops can just walk up and get any ordinary business records someone you do business with has created about you, courts continue to notice and declare illegal new ways in which naive application of that doctrine creates dragnets.