Re: Is this message is Official?

Indeed, it is to warn you that a newbie is PMing you.

I've found the actual post what caused Theymos to implement this:
Post: https://bitcointalk.org/index.php?topic=1029623.msg11217900#msg11217900
Scam transaction ID; https://blockchain.info/address/1MxUUsWjqCAE169sA1e8ZoqNXV4JvVcBmG

Theymos then implemented this, saying:

Quote from: theymos on May 01, 2015, 01:06:56 AM

Quote from: Micon on April 28, 2015, 01:29:56 AM

FYI to everyone in this thread, I was so happy to "win" my bitcointalk ad, I didn't check the username close enough before getting scammed for 3.6 btc:

Sorry for your loss. To hopefully make future cases of this sort of thing more difficult, I added a warning to all PMs by newbies.

--> https://bitcointalk.org/index.php?topic=1029623.msg11249135#msg11249135