Phone calls and in-person meetings are far less likely to end up leaving behind proof (provable in court) of information you passed to someone. If you send fil

Phone calls and in-person meetings are far less likely to end up leaving behind proof (provable in court) of information you passed to someone. If you send files, you have to first create or possess the files. That can leave behind hard evidence. Evidence that you bought a burner phone or met someone isn’t quite the same as evidence that you passed specific information. And if you're under surveillance, being shadowed, then clearly you're going to have a lot of trouble using any means.