Hilton HHonors - DOUBLE POINTS OFFER - Hilton Garden Inn

I just noticed this on my hilton.com statement of activity

I'm not complaining, mind you. But why am I getting double points, on top of my

DIAMOND VIP BONUS
and
50% BONUS ON BASE POINTS

??

If this was some promotion, I don't remember enrolling.

thanks, Hilton.com. I love the free trips to hawaii!!

I just noticed this on my hilton.com statement of activity

I'm not complaining, mind you. But why am I getting double points, on top of my

DIAMOND VIP BONUS
and
50% BONUS ON BASE POINTS

??

If this was some promotion, I don't remember enrolling.

thanks, Hilton.com. I love the free trips to hawaii!!
Many such promotions these days are targeted and don't require registration, but only apply in a narrow window and/or at some properties. Is it possible it was buried way down in one of those emaiils they send you that you deleted before reading all the way through? :)

Did you pay by American Express?