WRT boolean for SSL, I think it's very common for clients to verify server certificates, but relatively uncommon for servers to require client certificates.  The impression I have from reading docs and stack overflow posts that the most common use case for the SSL module is connection to HTTPS sites. For this use case, using a default context makes a lot of sense.

It seems extremely unlikely to me for a server to use a default context.

But I'm not an SSL expert.