RAAArty, Having looked at your OP again, there is nothing in the message you received that specifically mentions Mayhem.
It's worth bearing in mind that your details could have been lifted from the database of any other modelling site and/or friends computer/email address box, with the 'Yamato' reference in the message you received being purely coincidental.
No need to 'overcome' the system. Anyone who joins can click on the email icon under members names, which brings up the on-forum email page, then they send a mail to your email address, not on the forum, so no usernames displayed, just their email address.
Martin may be able to find the sender in the member list using the email address? Otherwise it's just a case of mark as spam, or hide your email address on the forum.
Not true. Your email icon is only visible to anyone registered IF you select the option in your profile settings that states
Allow users to email me.
I don't think that is correct. The recipient's e-mail address is hidden (unless you e-mail yourself). The "Allow users to email me" box does what it says - if unchecked then no-one (except admin I expect) can e-mail you from the forum.
The spammer in the OP has probably gone to each poster in that Yamato thread in turn, used the e-mail link and then pasted his text into each - one at a time. Which isn't really spamming at all as it is limited in volume and targeted at people that have shown interest. Quite sensible in fact.
Whether it is termed 'Spam', 'Junk' or just plain 'Unwanted', it can all be identified as 'Unsolicited'. Unsolicited email is electronic mail that an individual did not request, and it remains a widespread problem.
As Unsolicited email can contain or precede a phishing scam and/or lead to the propagation of worms and viruses by disguising itself in a recipients system, I don't consider it to be 'Quite sensible in fact', if a registered user is abusing the Mayhem system to bother the membership in this manner.
Consequently, I'll keep my fingers crossed that the source may be identified before too long.
Andy