I don't think anything needs to be done here. The default setting is default, and from the documentation, one of the possible values is:

A special value is default which is the implicit default setting of enabled.

(From https://www.samba.org/samba/docs/current/man-html/smb.conf.5.html).

Enabled and auto are synonymous, AFAICT.

By default, I discovered that there was no encryption at all being used.

Maybe add some note about encryption then? Maybe give the GLOBAL1=smb encrypt = mandatory as an example on how quoting works (pretty much no quoting, though spaces and stuff are magically ok).

(I went 'I need a network share on a Windows machine in 1-2 hours. WebDav (already up and high availability online), almost, almost! Nope. Ok, samba. Ok, initial setup done, what do we have here. smbstatus, encryption none. ..over the normal internet. ..? What? I'd assume if a thing doesn't want to go through Traefik, it will offer it's own encryption. Now how will we encrypt this (20 minutes(!) later, trying to get it with the docker thing, discovering it appends, not replaces and how to get the setting in to the config (quoting caused some problems as well)))

How to configure Docker for file encryption?

Add the env variables in the original comment.