So they could see him and know by seeing him that he arrived
safely; a text message could be sent by *anyone* who could've
intercepted them.

jms

{original post had no questions}

The issue of waste of bandwith is not as big a deal to an
advanced technology (from today's standards); also, any really good
telepath could rip out those codes and keys in about 10 seconds.
Further, they would've had a password to use (as in "the board," which
he used) to verify that he was all right and not being forced to make
the call.

jms

{original post had no questions}

In that scenario, there is no such thing as ANY kind of secure
communication, which puts us pretty much back where we started.

jms