[Russell91]

yes, but using a separate scp command requires a second round trip and second password/key authentication, which would double the wait time of the already slow ssh login process.

[dnet]

not, if you configure multiplexing (and why wouldn't you) https://en.wikibooks.org/wiki/OpenSSH/Cookbook/Multiplexing

[JoachimSchipper]

As an inferior option for older OpenSSH versions, you could also forward a port and send the tarball over that.

If people regularly send large directories, you might also want to extend this with rsync.

[mixmastamyk]

Interesting, I wonder if python fabric or its ssh libs could help.