Some jurisdictions have allowed that data collection under the Fourth Amendment, but, as The Times noted, in a 2012 decision, "five [Supreme Court] justices suggested that any long-term, automated collection of a person’s publicly displayed actions might raise Fourth Amendment issues." The stipulation presented to the Senate committee suggests that the Department of Justice decided the tests were allowed because the data had been acquired under the phone records collection. That's precisely the issue over which the Court has expressed uncertainty.
Mark Rumold, staff attorney for the Electronic Frontier Foundation, was blunt in the privacy organization's assessment of the report.
What I find particularly startling is that neither NSA nor DOJ thought it was important to alert the FISC before collecting cell site location information. That's either evidence of a complete disregard for the FISC or a complete disregard for the sensitivity of the information they were collecting — and it's probably evidence of both.