I am all for guild events and challenges, but I am hesitant of this one.
While the intent behind it is good, I feel that this may not be the best way to encourage greater membership.
I can wholeheartedly say that I will never actively offer someone membership with the guild without knowing the person irl. Sure, if they ask about us then I don't mind telling them about DA, but I really don't want to fill up the guild with people that will join and then not play anymore (which seems to be the current consensus on why the guild is struggling).
This is a new(ish) guild in an old game. Don't expect too much otherwise the disappointment will be high.
And, yes, I was recruited to the guild by burned in this mass spam method, but if I hadn't have known about AltsFTW beforehand, I would have never joined an "unknown" guild
Just my two cents.