The order under the SCA is not a warrent, and doesn't have the same standard of proof.

Specifically 18 U.S. Code § 2703 means the government can request location information [1] with a court order as described by (d). The standard for the court order is "reasonable grounds to believe that the contents ... are relevant and material to an ongoing criminal investigation".

reasonable grounds << probable cause

[1] under (c)(1)(D) as the cell location is not ljisted (c)(2)

that's interesting, but one could assume that if some member of a gang points out the leader of the gang to the police, the court would allow them to employ surveillance techniques needed to acquire evidence. Wouldn't that kind of information be sufficient to pass the Probable Cause test?