That a "blanket court order" writ was used. I saw on TV a show explaining the process of what these current eve dropping events got started and how it was implemented. One and after another all the phone providers complied after receiving the writ order. Those were the major comm. cos. and then they went after the smaller ones. Now and then someone came to realize just what was going on usually by some techie or one seeing usual equipment or features not normally present. In their scope of operations they saw something amiss. When they complained or suggest those same views, they were told to shut-up or keep quiet either buy the co. or feds. Only after some time when a smaller operation finally figured this is illegal and suited the feds., did it see light. That still didn't stop it all because in order to remain in operation all com. cos. need that FCC license to continue. If not renewed, effectively shutdown. Also, it made sense to comply as the feds are to be a trusted partner in all this. Regardless, the need was there but the implementation was supposedly illegal. The US-AG(at time) that was posed this process before it was started, didn't see it as legal, he disallowed it from his sick in the hospital. Of course using maneuvers as the US-AG wasn't capable of administrating of office, his temporary replacement did sign-off on this. Thus, the court order writs were practically Xeroxed and issued. The continuation maybe more controlled or covert but this normally would be done because the technology is there to do this, why not would reason the feds. Alas, the legally is still up in the air or unless challenged becomes an issue. The data is out of the bottle, can't seal it now.
Alas, Oh poor Yorick I knew him well .... -----Willy