And it's still a violation of the 4th amendment. Now, whether the fact that the violation occurred is surfaced in court, and successfully used to exonerate a defendant, is where the problems occur.
It is not a violation. Third Party Doctrine. You waive 4th Amendment once you share something with someone else. This is the same legal phenomena that pretty much guarantees LE will get access to card based financial activity, and telephone metadata.
They'll need a warrant for a wiretap, but tracing contact graph has been open season for as long as I've been around.
