"parallel construction" and third-party doctrine are two loopholes wrt 4A.
To what I imagine was everyone’s surprise, no one in the US really cares about 4a anymore. Nothing has changed since Snowden (in fact, the powers have managed to convince vast swaths that Snowden is the bad guy!), and it is pretty common knowledge that 4a is out the window with parallel construction and asset forfeiture…but it all still keeps churning.