Back in the day you could do off the books phone tapping with a set of alligator clips, a capacitor and a memo recorder. If you didn't want to do it yourself yo

Back in the day you could do off the books phone tapping with a set of alligator clips, a capacitor and a memo recorder. If you didn't want to do it yourself you could just get someone else to do it, preferably someone who works in a large central office (with or without phone company knowledge). The result was not usable in court, but it would save you immense amounts of time sitting around figuring out what criminals were doing. Things like Stingrays preserve the capability of off the books phone tapping. This sort of capability is very important for things like drug trafficking where none of the people involved are very likely to file a police report. So I suspect that the attitude of the law enforcement people involved is that they have been asked to do a job that is practically impossible without this capability.