I am sure this is the default personal message settings.
.And if you see someone is sending you unsolicited PMs, then simply use the "Report to admin button that will get them banned.
Times and seasons happen to everything in life, and that's what's happening to that feature now. Times have changed and we've to change to match up with it too. I think theymos should put up an option to block unsolicited PMs, not just the newbies option alone. What if the PMs aren't coming from a newbie? That means the feature won't be able to block such vexatious and scam PMs then?.And if you see someone is sending you unsolicited PMs, then simply use the "Report to admin button that will get them banned.