Actually it is not a bad rule.
On several boards I frequent there have been new members with "0" posts who join specifically to PM as many active members they can with SPAM.
Anything to curtail spam is OK in my book.
Sometimes I feel like if I answer any more questions it is like someone trying to climb over a fence to jump off a bridge and me giving them a boost.
Answers based on the 2008 & 2011 NEC.