DrByte:
Yes, it is enabled by default.
No, it will not be obvious. It does not include a CAPTCHA to nag humans to try to prove they're human.
What are the patterns of spam that you get? Certain kinds of phrases? Certain kinds of words/content in the subject? Certain kinds of content in the message body? Common IP address?
So I just got spammed with about 11 emails, I believe this may have been what filled my SPAM folder before I emptied it. I want to contribute so let me know what details you would like from the sender. They all had the exact same body, and it looks like the mail was generated using different phone numbers and email addresses each time. I got all 12 mails within 1 minute from first to last. Their is an office use only section at the bottom of the email that shows the same IP address for all the mail but I'm thinking that's not a real tell and more so just part of the body of the email. If you would like any other details from the source message just let me know, happy to provide them.
Taking a guess that this is what you may want in the source
Received: from mout.perfora.net (mout.perfora.net. [74.208.4.194])
by mx.google.com with ESMTPS id b8si15143ile.42.2020.11.24.11.52.06
This was at the footer of every mail:
Office Use Only:
From: RonaldBep
Mail: [B](random on each mail)[/B]
Login Name: Not logged in
Login Email: Not logged in
Telephone: Not logged in
IP Address: 212.102.37.238 - 212.102.37.238
Host Address: unn-212-102-37-238.cdn77.com
Date and Time: Tue Nov 24 2020 14:52:27 EST