Well, I doubt if it will work as the first link says:
<font face="Verdana, Arial, Helvetica, sans-serif" size="2">From the first M&M promotion link:
Only customers who received the mailing are entitled to register for this promotion.</font>
As a data specialist, I say, if it was my system, it wouldn't work. So let's hope they are less cautious or that they do not really care